Bypass gcc 4.4/4.5 compilation bug by moving -fomit-frame-pointer to Makefile.all.am

Bypass gcc 4.4/4.5 compilation bug by moving -fomit-frame-pointer to Makefile.all.am
gcc 4.4 and 4.5 has a bug which causes miscompilation of mc_main.c:
 args are not correctly given to VG_(am_munmap_valgrind).
This causes the secondary map entries to not be unmapped
(which can cause unlimited memory growth)
and/or causes the assert on VG_(am_munmap_valgrind) result to fail.

Removing the pragma optimize from mc_main.c and inserting it instead
in Makefile.all.am for x86 solves the gcc bug.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12564