CPP predefine conflict with getpc thunks

[David Miller]

Rephrasing this in an effort to get it past the moderator.

When gcc is targetting PENTIUM_PRO cpu target, it emits the CPP
predefined symbol __i686.

This breaks the build because all of the getpc thunks on x86 are
prefixed by "__i686.getpc..." which ends up being expanded to "1
.getpc..." by CPP

I've gotten the build to go through by configuring with CC="gcc
-U__i686" CXX="g++ -U__i686" but this really shouldn't be necessary to
get a successful build.

And on Fedora 12 on x86, gcc defaults to PENTIUM_PRO code generation.
So anyone who tries to build glibc on x86 is very likely to hit this
problem.

Maybe we can put the "-U__i686" in one of the x86 sysdep Makefiles?