Patch merged into coreboot/master: 8414d3c xcompile: always use -march=i686

the following patch was just integrated into master:
commit 8414d3c0b407d9afc6a2446dba3ca358da2c7bb6
Author: Aaron Durbin 
Date:   Thu Oct 10 12:44:11 2013 -0500

xcompile: always use -march=i686

When compiling coreboot for x86 on gcc the compiler is
    free to pick whatever defaults it is using at the time of
    gcc's compile/configuration when no -march is specified.
    Not properly specifying -march then opens up the use of SSE
    instructions for compilation units it should not be used such
    as the SMM module as this module doesn't save/restore SSE
    registers.

Change-Id: I64d4a6c5fa9fadb4b35bc7097458e992a094dcba
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://chromium-review.googlesource.com/172640
    Reviewed-by: Stefan Reinauer 
    (cherry picked from commit d49358f7959bb52c3e7ff67d37c21a1b294adf72)
    Signed-off-by: Isaac Christensen 
    Reviewed-on: http://review.coreboot.org/6716
    Tested-by: build bot (Jenkins)

See http://review.coreboot.org/6716 for details.

-gerrit