inttypes-h tests: Avoid compilation error on mingw. Reported by Michele Locati in <https://lists.gnu.org/archive/html/bug-gettext/2024-09/msg00015.html>. * tests/test-inttypes-h.c (l): On mingw without __USE_MINGW_ANSI_STDIO, don't test for the presence of SCN*8, SCN*LEAST8, SCN*FAST8}. * doc/posix-headers/inttypes.texi: Mention the mingw bug.