musl libc.so working and almost building with current pcc

[Isaac Dunham <ibid.ag@gmail.com>]

Hello,
Current (20160403) pcc almost builds a working libc.so.

(Unfortunately, it's still necessary to fix the pcc-libs package
by updating config.guess/config.sub and adding protected visibility;
I didn't add protected visibility and forced -fPIC, though the build
system seems to add -fPIC for some files.)

However, PCC reports a major internal compiler error at line 1382
of ldso/dynlink.c (which is conditional on FDPIC support).
If I convert the "if (DL_FDPIC) ..." to an ifdef, I get a working libc.
(src/complex/catanf.c is now properly compiled.)

I'd like to find out what's causing the ICE and report it, but reducing
the dynamic linker to a testcase isn't something that I'm ready to do.
If someone has any further ideas, that would be appreciated.

Thanks,
Isaac Dunham