x86-64 fixes: Part 4

[Kevin Ryde]

Andreas Jaeger <aj@suse.de> writes:
>
> mcount is not standardized yet.  But I'm currently looking in this
> area.

Incidentally, in the next release the x86 asm code will have support
for gcc -finstrument-functions, hopefully giving greater accuracy (or
the same accuracy in less time) than traditional prof/gprof.

Obviously there's nothing stopping anyone using any sort of profiling
on just the generic C code, but when that's a lot slower then the asm
code it doesn't make for a very realistic experiment.