OpenSubdiv: fix build on noatomic8 archs.

Not making this a change to the tbb package itself because SuiteSparse
(one of the other tbb dependencies which can be cross built) builds
without it. This decision can be revisited in the future, though.

srcpkgs/OpenSubdiv/template

@@ -21,6 +21,12 @@ if [ "$CROSS_BUILD" ]; then
 	configure_args+=" -DSTRINGIFY_LOCATION=/usr/bin/stringify"
 fi
 
+if [ "$XBPS_TARGET_NO_ATOMIC8" ]; then
+	makedepends+=" libatomic-devel"
+	configure_args+=" -DCMAKE_CXX_STANDARD_LIBRARIES=-latomic"
+fi
+
+
 OpenSubdiv-devel_package() {
 	depends="${sourcepkg}>=${version}_${revision}"
 	short_desc+=" - development files"