gcc optimization on BeOS (patch by François Revol <revol at free dot fr>)

Originally committed as revision 1151 to svn://svn.ffmpeg.org/ffmpeg/trunk

configure

@@ -75,6 +75,16 @@ BeOS)
 prefix="/boot/home/config"
 # helps building libavcodec
 CFLAGS="-O3 -DPIC -fomit-frame-pointer"
+# 3 gcc releases known for BeOS, each with ugly bugs
+gcc_version="$($cc -v 2>&1 | grep version | cut -d ' ' -f3-)"
+case "$gcc_version" in
+2.9-beos-991026*|2.9-beos-000224*) echo "R5/GG gcc"
+mmx="no"
+;;
+*20010315*) echo "BeBits gcc"
+CFLAGS="$CFLAGS -fno-expensive-optimizations"
+;;
+esac
 SHFLAGS=-nostart
 # disable linux things
 audio_oss="no"