http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53348
--- Comment #6 from Daniel Richard G. <skunk at iskunk dot org> 2012-05-15 19:01:45 UTC --- My first thought had been to put in AIX-version-dependent cpp conditionals in aix-stdint.h, but admittedly, that would have been an ugly way to go. I have an AIX 5.3 system here as well. There is no sys/inttypes.h, but [u]int_fastNN_t is defined in sys/stdint.h, and all the types are the same size as [u]intNN_t. This is presumably the case for newer AIXes as well. Fixincluding sys/inttypes.h should be safe IMO, and any bad fallout from that should be limited to AIX releases that still have this header, and use the unequal-sized-types, and somehow depend on those types. I'll double-check that this isn't the case for 4.3.