Add hacks.mk from pkgsrc's vlc21. Still needed.

(by the way, thank you for creating this package!)

vlc/hacks.mk

@@ -0,0 +1,15 @@
+# $NetBSD: hacks.mk,v 1.1 2015/05/01 07:57:45 tnn2 Exp $
+
+.if !defined(VLC21_HACKS_MK)
+VLC21_HACKS_MK=		# empty
+
+# vlc_atomic.h rightly assumes "uses clang (support for C11)" implies
+# "ships stdatomic.h" but for us this is not yet the case.
+# This hack should be removed when -current has stdatomic.h.
+.if	${OPSYS} == "NetBSD" &&		\
+	exists(/usr/bin/clang) &&	\
+	!exists(/usr/include/stdatomic.h)
+CPPFLAGS+=		-D__STDC_NO_ATOMICS__
+.endif
+
+.endif