[PATCH 2/7] Don't disable SSE in x86-64 ld.so

[Roland McGrath]

> We use -mno-mmx on i386 since mm registers are passed to pass
> __m64 arguments.  On x86-64, I can't think of a good reason to use
> MMX in ld.so.

The patch is OK now since -mno-mmx was the status quo ante for x86_64.

But the rationale for -mno-mmx is being stated in a backwards fashion.
We should add special options only if there is a good reason to have
them.  If you just don't think it's optimal to use MMX, then that is not
a good reason to use -mno-mmx; it's a good reason to make some compiler
change to improve optimization.  If there is a specific, known,
pathological optimization issue, then there should be a GCC bug filed
for that and the comments in the makefile should point to that bug.  If
there is no such reason to specifically use -mno-mmx, then we should
drop it.