stdinc: fix -Wformat warning on win64 ../libpkgconf/client.c: In function 'pkgconf_trace': ../libpkgconf/client.c:381:47: warning: format '%u' expects argument of type 'unsigned int', but argument 5 has type 'size_t' {aka 'long long unsigned int'} [-Wformat=] 381 | len = snprintf(errbuf, sizeof errbuf, "%s:" SIZE_FMT_SPECIFIER " [%s]: ", filename, lineno, funcname); | ^~~~~ ~~~~~~ | | | size_t {aka long long unsigned int} Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>