wrap: include xlocale.h header on macOS

Compiling the wrap filter fails on macOS because the locale.h header
does not include declarations for locale_t, freelocale, or newlocale.
Instead, these are included in the xlocale.h header.

We use a conditional include because glibc no longer ships the xlocale.h
header in its distribution.

Signed-off-by: Gregory Anders <[email protected]>
Acked-by: Robin Jarry <[email protected]>

filters/wrap.c

@@ -15,6 +15,10 @@
 #include <wchar.h>
 #include <wctype.h>
 
+#ifdef __APPLE__
+#include <xlocale.h>
+#endif
+
 static void usage(void)
 {
 	puts("usage: wrap [-h] [-w INT] [-r] [-l INT] [-f FILE]");