My CFLAGS from make.conf are
CFLAGS="-march=nocona -O2 -pipe"
but compilation runs with
-O4 -march=native -mtune=native
and a few others. Upstream's non-autoconf configure script seems to be adding them. I found this block in it:
# Checking for CFLAGS
if test "$_profile" != "" || test "$_debug" != "" ; then
CFLAGS="-W -Wall -O2 $_march $_mcpu $_pipe $_debug $_profile"
elif test -z "$CFLAGS" ; then
if test "$cc_vendor" = "intel" ; then
CFLAGS="-O2 $_march $_mcpu $_pipe -fomit-frame-pointer -wd167 -wd556 -wd144"
elif test "$cc_vendor" != "gnu" ; then
CFLAGS="-O2 $_march $_mcpu $_pipe"
CFLAGS="-Wall -Wno-switch -Wpointer-arith -Wredundant-decls -O4 $_march $_mcpu $_pipe -ffast-math -fomit-frame-pointer"
While mplayer-1.0_rc4_p20090919-r2.ebuild for some reason does not compile with -O4 and friends (maybe due to "Drop custom-cflags due to gcc-4 bug, filter flags, bug 269975" (ChangeLog)) the block above is still present in configure and may need further attention.
CC'ing Steve, as we spoke about it earlier.
@Sebastian: Please Assign bugs yourself (now that you have the Power).
*** This bug has been marked as a duplicate of bug 269975 ***