powerpc*-*-aix*. Add code to create appropriate exports files,
and pass appropriate compilation flags, and test against
appropriate expected output.
* ld-shared/xcoff.dat: New file.
* ld-shared/main.c: Put #ifndef XCOFF_TEST around tests that can
not be linked using XCOFF. Use shlib_shlibvar1 as a sample
function pointer, rather than shlib_mainvar.
* ld-shared/sh1.c: Likewise.
* ld-shared/shared.dat: Update for change from using shlib_mainvar
to using shlib_shlibvar1.
* ld-shared/sun4.dat: Likewise.
