[libunwind] unw_regname is defined differently to libgcc libunwind

[spauka]

It seems like LLVM libunwind is designed to be compatible with the libgcc libunwind api, as suggested in /libunwind/include/libunwind.h:

// Compatible with libunwind API documented at:
//   http://www.nongnu.org/libunwind/man/libunwind(3).html

However the definition of unw_regname is different between the two libraries.

LibGCC libunwind:

const char *unw_regname(unw_regnum_t);

LLVM libunwind:

const char *unw_regname(unw_cursor_t *, unw_regnum_t) LIBUNWIND_AVAIL;

Not sure if this is intentional?