diff -urN portage-2.3.0-orig/pym/portage/const.py portage-2.3.0/pym/portage/const.py
--- portage-2.3.0-orig/pym/portage/const.py	2016-05-16 18:40:38 +0900
+++ portage-2.3.0/pym/portage/const.py	2016-07-03 05:57:29 +0900
@@ -202,6 +202,8 @@
 	"xattr",
 ])
 
+SUPPORTED_FEATURES      |= frozenset(["concise-progress"])
+
 EAPI                     = 6
 
 HASHING_BLOCKSIZE        = 32768
diff -urN portage-2.3.0-orig/pym/portage/output.py portage-2.3.0/pym/portage/output.py
--- portage-2.3.0-orig/pym/portage/output.py	2016-06-02 04:54:34 +0900
+++ portage-2.3.0/pym/portage/output.py	2016-07-03 05:57:29 +0900
@@ -10,6 +10,7 @@
 import re
 import subprocess
 import sys
+import time
 
 import portage
 portage.proxy.lazyimport.lazyimport(globals(),
@@ -842,3 +843,101 @@
 
 codes = _LazyInitColorMap(codes)
 _styles = _LazyInitColorMap(_styles)
+
+class EProgressBar:
+	"""
+	Implements a textual progress bar.
+
+	@ivar progress: The current progress through the operation, in either
+		bytes or arbitrary units.
+	@type progress: IntType
+	@ivar total: The maximum value C{progress} is expected to reach, in the
+		same units as C{progress}.  If zero or negative, assumed to be
+		unknown.
+	@type total: IntType
+	@ivar is_bytes: True if C{progress} and C{total} are byte counters,
+		otherwise false.  Affects the manner in which the progress is
+		displayed.
+	@type is_bytes: Boolean
+	@ivar start_time: Time at which the operation was started (assumed to
+		be the time at which the progress bar was created).
+	@type start_time: Float
+	@ivar start_progress: The value of C{progress} when the operation was
+		started.
+	@type start_progress: IntType
+	@ivar term_columns: Width of terminal in characters. Defaults to the value
+		specified by the shell's C{COLUMNS} variable, else to the queried tty
+		size, else to C{80}.
+	@type term_columns: IntType
+	"""
+
+	def __init__(self, total, progress = 0, is_bytes = False):
+		self.total = total
+		self.progress = progress
+		self.is_bytes = is_bytes
+		self.start_time = time.time()
+		self.start_progress = self.progress
+		lines, columns = get_term_size()
+		if columns <= 0:
+			columns = 80
+		# Adjust columns so that eend works properly on a standard BSD console.
+		if os.environ.get("TERM") == "cons25":
+			columns = columns - 1
+		self.term_columns = columns
+
+	def __size_to_string(self, size):
+		if size >= 100000000000:
+			return "%uGB" % (size / 1000000000)
+		elif size >= 100000000:
+			return "%uMB" % (size / 1000000)
+		else:
+			return "%ukB" % (size / 1000)
+
+	def update(self, progress = -1):
+		"""
+		Optionally updates the current progress value, then draws the
+		progress bar on the terminal.
+
+		@param progress: I{(optional)} The current progress value.
+		@type progress: IntType
+		"""
+		if progress >= 0:
+			self.progress = progress
+		if self.is_bytes:
+			progress_string = self.__size_to_string(self.progress)
+			total_string = self.__size_to_string(self.total)
+		else:
+			progress_string = ""
+			total_string = "%d%%  " % (self.progress*100 / self.total)
+		if self.total > 0:
+			bar_size = self.term_columns - 27
+			time_string = "---:--"
+			elapsed_time = time.time() - self.start_time
+			elapsed_progress = self.progress - self.start_progress
+			progress_left = (self.total - self.start_progress) - elapsed_progress
+			if elapsed_time > 0 and elapsed_progress > 0 and progress_left >= 0:
+				import math
+				eta = int(math.ceil((elapsed_time * progress_left) / elapsed_progress))
+				if eta > 1000*60-1:
+					eta = 1000*60-1
+				time_string = "%3d:%02d" % (eta/60, eta%60)
+			if bar_size > 0:
+				bar_width = int(bar_size * min(self.progress / self.total, 1))
+				bar_string = "%-*s" % (bar_size, '=' * bar_width)
+				sys.stderr.write("%7s |%s| %7s  %s\r" \
+					% (progress_string, bar_string, total_string, time_string))
+			else:
+				sys.stderr.write("%7s/%-7s  %s\r" \
+					% (progress_string, total_string, time_string))
+		else:
+			sys.stderr.write("%7s\r" % progress_string)
+		sys.stdout.flush()
+
+	def finish(self):
+		"""
+		Draws the progress bar on the terminal, then advances to the next
+		line so that subsequent terminal output does not overwrite the
+		progress bar.
+		"""
+		self.update()
+		writemsg("\n")
diff -urN portage-2.3.0-orig/pym/portage/package/ebuild/digestcheck.py portage-2.3.0/pym/portage/package/ebuild/digestcheck.py
--- portage-2.3.0-orig/pym/portage/package/ebuild/digestcheck.py	2015-04-14 02:22:11 +0900
+++ portage-2.3.0/pym/portage/package/ebuild/digestcheck.py	2016-07-03 05:57:29 +0900
@@ -37,7 +37,8 @@
 			os.path.dirname(os.path.dirname(pkgdir)))
 		mf = mf.load_manifest(pkgdir, mysettings["DISTDIR"])
 	eout = EOutput()
-	eout.quiet = mysettings.get("PORTAGE_QUIET", None) == "1"
+	eout.quiet = mysettings.get("PORTAGE_QUIET", None) == "1" \
+			or "concise-progress" in mysettings.features
 	try:
 		if not mf.thin and strict and "PORTAGE_PARALLEL_FETCHONLY" not in mysettings:
 			if mf.fhashdict.get("EBUILD"):
diff -urN portage-2.3.0-orig/pym/portage/package/ebuild/doebuild.py portage-2.3.0/pym/portage/package/ebuild/doebuild.py
--- portage-2.3.0-orig/pym/portage/package/ebuild/doebuild.py	2016-06-02 04:54:34 +0900
+++ portage-2.3.0/pym/portage/package/ebuild/doebuild.py	2016-07-03 05:57:29 +0900
@@ -1125,6 +1125,15 @@
 					if not os.access(parent_dir, os.W_OK):
 						raise PermissionDenied(
 							"access('%s', os.W_OK)" % parent_dir)
+			# FIXME: doesn't work anymore (this all seems to be handled by the _emerge module now)
+			#if mydo=="install" and "concise-progress" in mysettings.features:
+			#	timingfile = os.path.join(
+			#		mysettings["PORTAGE_TIMINGDIR"], mysettings["PN"])
+			#	writemsg(">>> Building %s...\n" % mysettings.mycpv)
+			#	retval = portage.timing.timed_spawnebuild(timingfile,
+			#		"install", actionmap, mysettings, debug,
+			#		logfile=logfile, fd_pipes=fd_pipes, returnpid=returnpid)
+			#else:
 			retval = spawnebuild(mydo,
 				actionmap, mysettings, debug, logfile=logfile,
 				fd_pipes=fd_pipes, returnpid=returnpid)
diff -urN portage-2.3.0-orig/pym/portage/package/ebuild/fetch.py portage-2.3.0/pym/portage/package/ebuild/fetch.py
--- portage-2.3.0-orig/pym/portage/package/ebuild/fetch.py	2016-01-19 19:25:04 +0900
+++ portage-2.3.0/pym/portage/package/ebuild/fetch.py	2016-07-03 05:57:29 +0900
@@ -13,6 +13,7 @@
 import stat
 import sys
 import tempfile
+import time
 
 try:
 	from urllib.parse import urlparse
@@ -38,11 +39,12 @@
 	PortageException, TryAgain
 from portage.localization import _
 from portage.locks import lockfile, unlockfile
-from portage.output import colorize, EOutput
+from portage.output import colorize, EOutput, EProgressBar
 from portage.util import apply_recursive_permissions, \
 	apply_secpass_permissions, ensure_dirs, grabdict, shlex_split, \
 	varexpand, writemsg, writemsg_level, writemsg_stdout
 from portage.process import spawn
+import portage.timing
 
 _userpriv_spawn_kwargs = (
 	("uid",    portage_uid),
@@ -54,7 +56,7 @@
 def _hide_url_passwd(url):
 	return re.sub(r'//(.+):.+@(.+)', r'//\1:*password*@\2', url)
 
-def _spawn_fetch(settings, args, **kwargs):
+def _spawn_fetch(settings, args, progress_bar=None, myfile_path=None, fetched_size=0, **kwargs):
 	"""
 	Spawn a process with appropriate settings for fetching, including
 	userfetch and selinux support.
@@ -73,6 +75,17 @@
 			2 : sys.__stdout__.fileno(),
 		}
 
+	if progress_bar:
+		# Run asynchronously so we can watch the file progress
+		kwargs["returnpid"] = True
+		# Hide stdout/err so we don't disturb the progress bar
+		try:
+			fd = os.open("/dev/null", os.O_RDONLY)
+			kwargs["fd_pipes"][1] = fd
+			kwargs["fd_pipes"][2] = fd
+		except OSError as e:
+			pass
+
 	logname = None
 	if "userfetch" in settings.features and \
 		os.getuid() == 0 and portage_gid and portage_uid and \
@@ -106,6 +119,31 @@
 		else:
 			settings['EBUILD_PHASE'] = phase_backup
 
+	if progress_bar:
+		# Wait for the process to complete, updating the
+		# file size as we go
+		mypid = rval[-1]
+		while mypid != 0:
+			# Check for process completion (do this first,
+			# so we get the final file size
+			rval = os.waitpid(mypid, os.WNOHANG)
+			if rval[0] == mypid:
+				mypid = 0
+			# Update the progress bar with the current file size
+			try:
+				filesize = os.stat(myfile_path).st_size
+				progress_bar.update(fetched_size + filesize)
+			except EnvironmentError:
+				pass
+			# Wait a bit so we don't sit on the CPU too much
+			time.sleep(0.1)
+		portage.process.spawned_pids.remove(rval[0])
+		rval = rval[1]
+		if rval != os.EX_OK:
+			if rval & 0xff:
+				rval = (rval & 0xff) << 8
+			rval = rval >> 8
+
 	return rval
 
 _userpriv_test_write_file_cache = {}
@@ -552,14 +590,20 @@
 	failed_files = set()
 	restrict_fetch_msg = False
 
+	concise_progress = "concise-progress" in features
+
+	total_size = 0    # Total size to fetch in bytes, negative = unknown
+	fetched_size = 0  # Amount fetched so far in bytes
+	filestatus = {}   # Status of each file (see below)
+	filelocks = {}    # Lock for each file
 	for myfile in filedict:
 		"""
-		fetched  status
-		0        nonexistent
-		1        partially downloaded
-		2        completely downloaded
+		filestatus
+		0 = nonexistent
+		1 = partially downloaded
+		2 = completely downloaded
 		"""
-		fetched = 0
+		filestatus[myfile] = 0
 
 		orig_digests = mydigests.get(myfile, {})
 
@@ -603,7 +647,7 @@
 		myfile_path = os.path.join(mysettings["DISTDIR"], myfile)
 		has_space = True
 		has_space_superuser = True
-		file_lock = None
+		filelocks[myfile] = None
 		if listonly:
 			writemsg_stdout("\n", noiselevel=-1)
 		else:
@@ -648,18 +692,19 @@
 					lock_kwargs["flags"] = os.O_NONBLOCK
 
 				try:
-					file_lock = lockfile(myfile_path,
+					filelocks[myfile] = lockfile(myfile_path,
 						wantnewlockfile=1, **lock_kwargs)
 				except TryAgain:
 					writemsg(_(">>> File '%s' is already locked by "
 						"another fetcher. Continuing...\n") % myfile,
 						noiselevel=-1)
 					continue
-		try:
-			if not listonly:
+
+			if not listonly:  # no longer needed, but left in to avoid unindentation creating huge diffs  --AC
 
 				eout = EOutput()
-				eout.quiet = mysettings.get("PORTAGE_QUIET") == "1"
+				eout.quiet = concise_progress or \
+					mysettings.get("PORTAGE_QUIET") == "1"
 				match, mystat = _check_distfile(
 					myfile_path, pruned_digests, eout, hash_filter=hash_filter)
 				if match:
@@ -676,6 +721,7 @@
 								writemsg(_("!!! Failed to adjust permissions:"
 									" %s\n") % str(e), noiselevel=-1)
 							del e
+					filestatus[myfile] = 2
 					continue
 
 				if distdir_writable and mystat is None:
@@ -745,6 +791,7 @@
 								raise
 							del e
 						os.symlink(readonly_file, myfile_path)
+						filestatus[myfile] = 2
 						continue
 
 				# this message is shown only after we know that
@@ -773,6 +820,11 @@
 								raise
 							del e
 
+				if myfile not in mydigests:
+					total_size = -1  # At least one file has an unknown size, so give up on counting
+				elif total_size >= 0:
+					total_size += mydigests[myfile]["size"]
+
 				try:
 					mystat = os.stat(myfile_path)
 				except OSError as e:
@@ -809,11 +861,12 @@
 						if (mydigests[myfile].get("size") is not None
 								and mystat.st_size < mydigests[myfile]["size"]
 								and not restrict_fetch):
-							fetched = 1 # Try to resume this download.
+							filestatus[myfile] = 1 # Try to resume this download.
+							fetched_size += mystat.st_size
 						elif parallel_fetchonly and \
 							mystat.st_size == mydigests[myfile]["size"]:
 							eout = EOutput()
-							eout.quiet = \
+							eout.quiet = concise_progress or \
 								mysettings.get("PORTAGE_QUIET") == "1"
 							eout.ebegin(
 								"%s size ;-)" % (myfile, ))
@@ -843,7 +896,7 @@
 										temp_filename, noiselevel=-1)
 							else:
 								eout = EOutput()
-								eout.quiet = \
+								eout.quiet = concise_progress or \
 									mysettings.get("PORTAGE_QUIET", None) == "1"
 								if digests:
 									digests = list(digests)
@@ -851,8 +904,26 @@
 									eout.ebegin(
 										"%s %s ;-)" % (myfile, " ".join(digests)))
 									eout.eend(0)
-								continue # fetch any remaining files
-
+								if total_size >= 0:
+									total_size -= mydigests[myfile]["size"]
+								filestatus[myfile] = 2  # No need to fetch this one
+
+	progress_bar = None
+	if concise_progress and not listonly and total_size != 0:
+		progress_bar = EProgressBar(total_size, fetched_size, is_bytes=1)
+	for myfile in filedict:
+		myfile_path = os.path.join(mysettings["DISTDIR"], myfile)
+		if progress_bar:
+			# If it's a partially-completed file, the file size will be
+			# already included in fetched_size.  Show the progress bar
+			# as is, then remove this file's contribution (since we'll
+			# add it back in later on).
+			progress_bar.update(fetched_size)
+			try:
+				fetched_size -= os.stat(myfile_path).st_size
+			except EnvironmentError:
+				pass
+		try:
 			# Create a reversed list since that is optimal for list.pop().
 			uri_list = filedict[myfile][:]
 			uri_list.reverse()
@@ -925,7 +996,9 @@
 						return 0
 
 				if not can_fetch:
-					if fetched != 2:
+					if filestatus[myfile] != 2:
+						if progress_bar:
+							progress_bar.finish()
 						try:
 							mysize = os.stat(myfile_path).st_size
 						except OSError as e:
@@ -947,16 +1020,16 @@
 					else:
 						continue
 
-				if fetched != 2 and has_space:
+				if filestatus[myfile] != 2 and has_space:
 					#we either need to resume or start the download
-					if fetched == 1:
+					if filestatus[myfile] == 1:
 						try:
 							mystat = os.stat(myfile_path)
 						except OSError as e:
 							if e.errno not in (errno.ENOENT, errno.ESTALE):
 								raise
 							del e
-							fetched = 0
+							filestatus[myfile] = 0
 						else:
 							if mystat.st_size < fetch_resume_size:
 								writemsg(_(">>> Deleting distfile with size "
@@ -969,18 +1042,20 @@
 										(errno.ENOENT, errno.ESTALE):
 										raise
 									del e
-								fetched = 0
-					if fetched == 1:
+								filestatus[myfile] = 0
+					if filestatus[myfile] == 1:
 						#resume mode:
-						writemsg(_(">>> Resuming download...\n"))
+						if not progress_bar:
+							writemsg(_(">>> Resuming download...\n"))
 						locfetch=resumecommand
 						command_var = resumecommand_var
 					else:
 						#normal mode:
 						locfetch=fetchcommand
 						command_var = fetchcommand_var
-					writemsg_stdout(_(">>> Downloading '%s'\n") % \
-						_hide_url_passwd(loc))
+					if not progress_bar:
+						writemsg_stdout(_(">>> Downloading '%s'\n") % \
+							_hide_url_passwd(loc))
 					variables = {
 						"URI":     loc,
 						"FILE":    myfile
@@ -996,7 +1071,7 @@
 					myret = -1
 					try:
 
-						myret = _spawn_fetch(mysettings, myfetch)
+						myret = _spawn_fetch(mysettings, myfetch, progress_bar, myfile_path, fetched_size)
 
 					finally:
 						try:
@@ -1006,6 +1081,8 @@
 							pass
 						except PortageException as e:
 							if not os.access(myfile_path, os.R_OK):
+								if progress_bar:
+									progress_bar.finish()
 								writemsg(_("!!! Failed to adjust permissions:"
 									" %s\n") % str(e), noiselevel=-1)
 							del e
@@ -1016,7 +1093,7 @@
 					try:
 						if os.stat(myfile_path).st_size == 0:
 							os.unlink(myfile_path)
-							fetched = 0
+							filestatus[myfile] = 0
 							continue
 					except EnvironmentError:
 						pass
@@ -1028,7 +1105,7 @@
 							if e.errno not in (errno.ENOENT, errno.ESTALE):
 								raise
 							del e
-							fetched = 0
+							filestatus[myfile] = 0
 						else:
 
 							if stat.S_ISDIR(mystat.st_mode):
@@ -1072,11 +1149,11 @@
 											try:
 												os.unlink(mysettings["DISTDIR"]+"/"+myfile)
 												writemsg(_(">>> Deleting invalid distfile. (Improper 404 redirect from server.)\n"))
-												fetched = 0
+												filesystus[myfile] = 0
 												continue
 											except (IOError, OSError):
 												pass
-								fetched = 1
+								filestatus[myfile] = 1
 								continue
 							if True:
 								# File is the correct size--check the checksums for the fetched
@@ -1088,6 +1165,8 @@
 									digests = _apply_hash_filter(digests, hash_filter)
 								verified_ok, reason = verify_all(myfile_path, digests)
 								if not verified_ok:
+									if progress_bar:
+										progress_bar.finish()
 									writemsg(_("!!! Fetched file: %s VERIFY FAILED!\n") % myfile,
 										noiselevel=-1)
 									writemsg(_("!!! Reason: %s\n") % reason[0],
@@ -1102,7 +1181,7 @@
 									writemsg_stdout(_("Refetching... "
 										"File renamed to '%s'\n\n") % \
 										temp_filename, noiselevel=-1)
-									fetched=0
+									filestatus[myfile] = 0
 									checksum_failure_count += 1
 									if checksum_failure_count == \
 										checksum_failure_primaryuri:
@@ -1119,28 +1198,35 @@
 										break
 								else:
 									eout = EOutput()
-									eout.quiet = mysettings.get("PORTAGE_QUIET", None) == "1"
+									eout.quiet = progress_bar or \
+										mysettings.get("PORTAGE_QUIET", None) == "1"
 									if digests:
 										eout.ebegin("%s %s ;-)" % \
 											(myfile, " ".join(sorted(digests))))
 										eout.eend(0)
-									fetched=2
+									filestatus[myfile] = 2
 									break
 					else:
 						if not myret:
-							fetched=2
+							filestatus[myfile] = 2
 							break
 						elif mydigests!=None:
 							writemsg(_("No digest file available and download failed.\n\n"),
 								noiselevel=-1)
 		finally:
-			if use_locks and file_lock:
-				unlockfile(file_lock)
-				file_lock = None
+			if use_locks and filelocks[myfile]:
+				unlockfile(filelocks[myfile])
+				filelocks[myfile] = None
 
 		if listonly:
 			writemsg_stdout("\n", noiselevel=-1)
-		if fetched != 2:
+		if progress_bar:
+			# Save the final progress from this file
+			fetched_size = progress_bar.progress;
+		if filestatus[myfile] != 2:
+			if progress_bar:
+				progress_bar.finish()
+				progress_bar = None
 			if restrict_fetch and not restrict_fetch_msg:
 				restrict_fetch_msg = True
 				msg = _("\n!!! %s/%s"
@@ -1172,4 +1258,8 @@
 			return 0
 	if failed_files:
 		return 0
+
+	if progress_bar:
+		progress_bar.finish()
+
 	return 1
diff -urN portage-2.3.0-orig/pym/portage/timing.py portage-2.3.0/pym/portage/timing.py
--- portage-2.3.0-orig/pym/portage/timing.py	1970-01-01 09:00:00 +0900
+++ portage-2.3.0/pym/portage/timing.py	2016-07-03 05:57:29 +0900
@@ -0,0 +1,330 @@
+# portage_timing.py -- routines to time build execution
+# Written by Andrew Church <achurch@achurch.org>
+# This source code is public domain.
+
+import os, re, select, sys, time
+import portage
+portage.proxy.lazyimport.lazyimport(globals(),
+	'portage.util:writemsg', 'portage.util:writemsg_stdout',
+	'portage.versions:pkgsplit', 'output',
+)
+
+
+# Output recorded from the current build:
+timing_output = []
+# Time at which each line in timing_output[] was recorded:
+timing_outtimes = []
+# Current position in timing_{output,times}[]: (to avoid having to extend
+# the array every time a new element is added)
+timing_outpos = 0
+
+
+def read_timing(timingfile):
+	"""
+	Read a possibly compressed timing file, returning the timing template
+	as an array of 3-element arrays: the first element of each subarray is
+	the elapsed time in microseconds between that line and the next, the
+	second element is the line itself as a string (with no trailing
+	newline), and the third is the completion fraction at the time the line
+	is first seen.  The timing template array is terminated by an entry
+	whose first (time) element is the total execution time in microseconds,
+	whose third (fraction) element is 1.0, and whose remaining elements are
+	undefined.
+
+	@param timingfile Full pathname of the timing file, without any
+		compression extension.
+	@type timingfile String
+	"""
+	try:
+		f = open(timingfile, "r")
+		timing = []
+		for line in f:
+			timestamp, command = line.split(" ", 1)
+			command = command.strip("\n")
+			timing.append([int(timestamp), command, 0.0])
+		f.close()
+		total = 0
+		for entry in timing:
+			entry[2] = (total * 1.0) / timing[-1][0]
+			total += entry[0]
+		return timing
+	except EnvironmentError:
+		# FIXME: compression not handled at present
+		return None
+
+
+def write_timing(timingfile):
+	"""
+	Write a new timing file from the timing_output[] and timing_outtimes[]
+	arrays.
+
+	@param timingfile Full pathname of the timing file, without any
+		compression extension.
+	@type timingfile String
+	"""
+
+	try:
+		timing_outtimes.append(None)  # just in case
+		timing_outtimes[timing_outpos] = time.time()
+		f = open(timingfile, "w")
+		total = 0
+		for i in range(0, timing_outpos):
+			line_time = int((timing_outtimes[i+1] - timing_outtimes[i]) * 1000000)
+			f.write("%u %s\n" % (line_time, timing_output[i]))
+			total += line_time
+		f.write("%u -\n" % total)
+		f.close()
+		# FIXME: compression not handled at present
+	except EnvironmentError:
+		pass
+
+
+def timed_spawnebuild(timingfile, mydo, actionmap, mysettings, debug,
+	alwaysdep=0, logfile=None, fd_pipes=None, returnpid=False):
+	"""
+	Call spawnebuild() in a subprocess, comparing the output to a template
+	file to display a progress bar instead of the raw output (if the
+	template file is unavailable, the raw output is shown).  If the
+	operation succeeds, the output and timing information is recorded in
+	the same template file for future reference.
+
+	@param timingfile Full pathname of the timing file, without any
+		compression extension.
+	@type timingfile String
+
+	The remaining parameters are as for spawnebuild().
+	"""
+
+	# Read in the timing file, if it exists, and initialize the template
+	# index.
+	timing = read_timing(timingfile)
+	timing_index = -1
+
+	# Allocate a pseudo-TTY for reading output from the subprocess.  If we
+	# can't, just give up and run the build normally.
+	master_fd = None
+	slave_fd = None
+	from pty import openpty
+	try:
+		master_fd, slave_fd = openpty()
+	except EnvironmentError as e:
+		writemsg("openpty failed: '%s'\n" % str(e), noiselevel=1)
+		del e
+		return portage.spawnebuild(mydo, actionmap, mysettings, debug,
+			alwaysdep, logfile, fd_pipes, returnpid)
+
+	# Run spawnebuild() in a subprocess, with output redirected to our
+	# pseudo-TTY.
+	pid = os.fork()
+	if pid == 0:
+		os.close(0)
+		try:
+			null_fd = os.open("/dev/null", os.O_RDONLY)
+			if null_fd != 0:
+				os.dup2(null_fd, 0)
+				os.close(null_fd)
+		except EnvironmentError:
+			pass
+		os.dup2(slave_fd, 1)
+		os.dup2(slave_fd, 2)
+		os.close(master_fd)
+		os.close(slave_fd)
+		retval = portage.spawnebuild(mydo, actionmap, mysettings, debug,
+			alwaysdep, logfile)
+		sys.exit(retval)
+	else:
+		os.close(slave_fd)
+		import fcntl
+		fcntl.fcntl(master_fd, fcntl.F_SETFL,
+			fcntl.fcntl(master_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
+
+	# Set up a progress bar if we have a timing template.
+	progress_bar = None
+	if timing:
+		progress_bar = output.EProgressBar(timing[-1][0])
+		progress_bar.update(0)
+	last_update = time.time()
+
+	# Clear the new timing data.
+	global timing_output, timing_outtimes, timing_outpos
+	timing_output   = []
+	timing_outtimes = []
+	timing_outpos   = 0
+
+	# Read output from the subprocess until it completes, updating the new
+	# timing template for each line read.
+	master_file = os.fdopen(master_fd, "r")
+	saved_line = ""  # In case we only get a partial line when reading
+	eof = False      # Becomes true when we get an EOF from the pseudo-TTY
+	finished = False # Becomes true when the subprocess exits
+	result = None    # Result code from the subprocess
+	while not finished or not eof:
+		# Check for subprocess completion.
+		waitres = os.waitpid(pid, os.WNOHANG)
+		if waitres and waitres[0] == pid:
+			finished = True
+			if waitres[1] == os.EX_OK:
+				result = os.EX_OK
+			elif waitres[1] & 0xFF:
+				result = (waitres[1] & 0xFF) << 8
+			else:
+				result = waitres[1] >> 8
+		# Check for build output.
+		events = select.select([master_file], [], [], 0.1)
+		if events:
+			s = None
+			try:
+				s = master_file.read(1000)
+			except IOError:
+				eof = True
+			if s is None:
+				if len(saved_line) > 0:
+					# The final line didn't end with a newline, so add one.
+					s = "\n"
+				s = ""
+				eof = True
+			elif s == "":
+				break  # No more output this time around
+			saved_line += s
+			now = time.time()
+			index = saved_line.find("\n")
+			while index >= 0:
+				line = saved_line[0:index]
+				saved_line = saved_line[index+1:]
+				timing_index = add_line(line, timing, timing_index, \
+					master_file, mysettings)
+				if not timing:
+					writemsg_stdout("%s\n" % line);
+				index = saved_line.find("\n")
+		# Update the progress bar (but not too frequently).
+		if timing and now - last_update >= 0.01:
+			# Calculate the rate at which we're progressing relative to the
+			# data recorded in the template.
+			rate = 0
+			if timing_index >= 0 and timing_outpos > 0 \
+			                     and timing[timing_index][2] > 0:
+				rate = (timing_outtimes[timing_outpos-1] - timing_outtimes[0]) \
+				       / (timing[-1][0]/1000000.0 * timing[timing_index][2])
+			# Calculate the percentage complete, including partial processing
+			# for the current line.
+			pct = 0
+			if timing_index >= 0:
+				pct = timing[timing_index][2]
+			if rate > 0 and now > timing_outtimes[timing_outpos-1]:
+				extra_time = now - timing_outtimes[timing_outpos-1]
+				extra_pct = (extra_time / rate) / (timing[-1][0] / 1000000.0)
+				if extra_pct > timing[timing_index+1][2] - pct:
+					extra_pct = timing[timing_index+1][2] - pct
+				pct += extra_pct
+			# Update the progress bar, making sure it uses our idea of the
+			# starting time.
+			if timing_outpos > 0:
+				progress_bar.start_time = timing_outtimes[0]
+			progress_bar.update(int(timing[-1][0] * pct))
+			# Save the last update time to avoid over-frequent updates.
+			last_update = now
+	# while not finished
+
+	# Finish off the progress bar.
+	if timing:
+		progress_bar.progress = progress_bar.total
+		progress_bar.finish()
+
+	# Write out the new timing data
+	if result == os.EX_OK:
+		write_timing(timingfile)
+
+	# Return the build result
+	return result
+
+
+# Variables used by add_line:
+search_last = 0
+search_wait = 0
+search_max = 0
+
+def add_line(line, timing, timing_index, master_file, mysettings):
+	"""
+	Process a line of output from the build subprocess.
+
+	@param line: The line of text, without any trailing newline.
+	@type line: String
+	@param timing: The timing template, or None if not available.
+	@type timing: Array
+	@param timing_index: The current index into the timing template.
+	@type timing_index: Integer
+	@param master_file: Pseudo-TTY from which build output is read.
+	@type master_file: Filehandle
+	@param mysettings: Portage configuration.
+	@type mysettings: Instance of portage.config
+	@returns The new timing index, or 0 if no template is available.
+	"""
+
+	global timing_output, timing_outtimes, timing_outpos
+
+	now = time.time()
+
+	# First, append the line to the output arrays.  Massage the line a bit
+	# so that changes in version number, compilation options and the like
+	# don't cause mismatches later on.
+	package, version = pkgsplit(mysettings.mycpv.split("/",1)[1])[0:2]
+	line = re.sub(r'\s+', r' ', line)
+	line = line.replace(package+'-'+version, package+'-VER')
+	line = re.sub(r'(^|\W)(cc|gcc|xgcc|gcc3|icc)(\W)', r'\1CC\3', line)
+	line = re.sub(r'(^|\W)(c\+\+|g\+\+|g\+\+3)(\W)', r'\1CXX\3', line)
+	if re.match(r'^\s*(cd\s+\S+\s*;\s*)?(if\s+)?(stage\d\/)?(CC|CXX)[^=]', line):
+		line = re.sub(r'(\s+-(-\S+|[^-\s]\S*))+', r' -OPTS', line)
+	if timing_outpos >= len(timing_output):
+		# Extend the arrays in big jumps for efficiency
+		timing_output.append([None]*1000)
+		timing_outtimes.append([None]*1000)
+	timing_output[timing_outpos] = line
+	timing_outtimes[timing_outpos] = now
+	timing_outpos += 1
+
+	# Now look for a matching line in the template (if we don't have a
+	# template, just return 0).
+	if not timing:
+		return 0
+	global search_last  # Time of last search
+	global search_wait  # Time in seconds to wait before the next search
+	global search_max   # Maximum time in seconds to search
+	# If the next line matches, use it.
+	if timing[timing_index+1][1] == line:
+		search_wait = 0
+		search_max = 0.05
+		return timing_index+1
+	# Otherwise we have to search.  But don't do so on every line, or we
+	# could eat huge amounts of CPU time if the build output differs from
+	# the template.
+	if time.time() - search_last < search_wait:
+		return timing_index
+	# Search forward for a matching line until we hit our time limit, but
+	# don't keep the build process waiting if it has more output for us.
+	found = False
+	got_output = False
+	search_limit = time.time() + search_max
+	index = timing_index + 2
+	while index < len(timing)-1 and time.time() - search_limit:
+		if timing[index][1] == line:
+			found = True
+			break
+		if not got_output and select.select([master_file], [], [], 0):
+			got_output = True
+			search_limit = time.time() + 0.01
+		index += 1
+	# Save the time this search ended.
+	search_last = time.time()
+	# If we found a match, return it; otherwise try harder next time.
+	if found:
+		search_wait = 0;
+		search_max = 0.05;
+		return index
+	else:
+		search_wait += 0.05
+		if search_wait > 3:
+			search_wait = 3
+		search_max += 0.05
+		if search_wait > 1:
+			search_wait = 1
+		return timing_index