illumos gate

GCC generates a .debug_macro section, to attempt to make macro knowledge sharable by various input .debug_macinfo sections (I think).

This falls into the classic need for sloppy relocation, where the .debug_macro sections it outputs (per-header) are elligible for comdat, and the .debug_macinfo section is not. We should use the gensym'd name of these sections to clue ourselves that we need sloppy relocation.