posixtm: pacify latest GCC
Also, modernize while I’m at it.
* lib/posixtm.c: Include c-ctype.h, idx.h, intprops.h, verify.h
instead of stdlib.h.
(ISDIGIT): Remove. All uses replaced by c_isdigit.
(year, posix_time_parse): Prefer idx_t to size_t. Use assume
instead of abort.
(posixtime): Do not parse twice; once is enough. That way, we
needn’t worry about a bogus warning about strcpy overrunning a
buffer from GCC 11.1.1
20210531 (Red Hat 11.1.1-3) x86-64
when coreutils is configured with --enable-gcc-warnings.
* modules/posixtm (Depends-on): Add c-ctype, intprops, verify.
Remove stpcpy.