progreloc: Speed up executable lookup on various platforms. * lib/progreloc.c: Include <errno.h>. (safe_read, full_read): New functions. (find_executable): On GNU/kFreeBSD, FreeBSD, DragonFly, NetBSD, Solaris, prefer the information from the /proc file system to a PATH search.

#include <stddef.h>
void mpsort (void const **, size_t, int (*) (void const *, void const *));