maint: preprocessor changes to support z/OS * lib/alloca.in.h, lib/fnmatch.c, lib/get-rusage-as.c: * lib/glob.c, lib/math.in.h, lib/ptsname_r.c: * tests/infinity.h, tests/nan.h, tests/test-canonicalize-lgpl.c: * tests/test-nonblocking-pipe.h: