[Bug libitm/53113] Build fails in x86_avx.cc if AVX disabled but supported by as (Solaris & Linux)

[dirtyepic at gentoo dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53113

--- Comment #9 from Ryan Hill <dirtyepic at gentoo dot org> 2013-02-22 02:31:03 UTC ---
Well, the trouble is nowadays that many CPUs are exactly "this, except without
that".  But anyways, the test is fragile.  There is no reason something like
-march=core2 -mno-sse3 should cause this to fail (I don't think it should even
try to build it in the first place, but I'm sure there must be a reason).  So
if this code expects and requires -mavx to compile, append it after the user's
CFLAGS rather than letting them blow their feet off.