diff -Nur libav.orig/libav-10.1-r1.ebuild libav.new/libav-10.1-r1.ebuild
--- libav.orig/libav-10.1-r1.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.1-r1.ebuild	2014-10-05 12:34:14.580751753 +0200
@@ -240,6 +240,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-10.1.ebuild libav.new/libav-10.1.ebuild
--- libav.orig/libav-10.1.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.1.ebuild	2014-10-05 12:37:46.237423438 +0200
@@ -228,6 +228,17 @@
 	# Option to force building pic
 	use pic && myconf+=" --enable-pic"
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=" --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}-"
diff -Nur libav.orig/libav-10.2.ebuild libav.new/libav-10.2.ebuild
--- libav.orig/libav-10.2.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.2.ebuild	2014-10-05 12:31:10.587414053 +0200
@@ -240,6 +240,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-10.3.ebuild libav.new/libav-10.3.ebuild
--- libav.orig/libav-10.3.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.3.ebuild	2014-10-05 12:31:45.254081520 +0200
@@ -242,6 +242,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-10.9999.ebuild libav.new/libav-10.9999.ebuild
--- libav.orig/libav-10.9999.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.9999.ebuild	2014-10-05 12:32:20.867415700 +0200
@@ -245,6 +245,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-10.ebuild libav.new/libav-10.ebuild
--- libav.orig/libav-10.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-10.ebuild	2014-10-05 12:32:49.414083056 +0200
@@ -226,6 +226,17 @@
 	# Option to force building pic
 	use pic && myconf+=" --enable-pic"
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=" --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}-"
diff -Nur libav.orig/libav-11.ebuild libav.new/libav-11.ebuild
--- libav.orig/libav-11.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-11.ebuild	2014-10-05 12:33:18.040750581 +0200
@@ -250,6 +250,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-9.14.ebuild libav.new/libav-9.14.ebuild
--- libav.orig/libav-9.14.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-9.14.ebuild	2014-10-05 12:33:45.510751043 +0200
@@ -240,6 +240,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-9.16.ebuild libav.new/libav-9.16.ebuild
--- libav.orig/libav-9.16.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-9.16.ebuild	2014-10-05 12:35:02.677419546 +0200
@@ -240,6 +240,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-9.9999.ebuild libav.new/libav-9.9999.ebuild
--- libav.orig/libav-9.9999.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-9.9999.ebuild	2014-10-05 12:35:38.600754024 +0200
@@ -240,6 +240,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )
diff -Nur libav.orig/libav-9999.ebuild libav.new/libav-9999.ebuild
--- libav.orig/libav-9999.ebuild	2014-10-05 12:28:08.704076371 +0200
+++ libav.new/libav-9999.ebuild	2014-10-05 12:36:09.730754576 +0200
@@ -250,6 +250,17 @@
 	# Option to force building pic
 	use pic && myconf+=( --enable-pic )
 
+	# Try to get cpu type based on CFLAGS.
+	# Bug #172723
+	# We need to do this so that features of that CPU will be better used
+	# If they contain an unknown CPU it will not hurt since ffmpeg's configure
+	# will just ignore it.
+	for i in $(get-flag march) $(get-flag mcpu) $(get-flag mtune) ; do
+		[ "${i}" = "native" ] && i="host" # bug #273421
+		myconf="${myconf} --cpu=${i}"
+		break
+	done
+
 	# cross compile support
 	if tc-is-cross-compiler ; then
 		myconf+=( --enable-cross-compile --arch=$(tc-arch-kernel) --cross-prefix=${CHOST}- )