If this is Windows specific, it can be inside ifeq ($(OS),WNT)

This also prevents a weird problem I see when cross-compiling in one tree (but
not in other trees for other cross-compilation targets).

Change-Id: I102e652c259a66ea124b344bd229e8988801ac58

vcl/Library_vcl.mk

@@ -661,8 +661,10 @@ endif
 # Runtime dependency for unit-tests
 $(eval $(call gb_Library_use_restarget,vcl,vcl))
 
+ifeq ($(OS),WNT)
 # HACK: dependency on icon themes so running unit tests don't
 # prevent delivering these by having open file handles on WNT
 $(eval $(call gb_Library_use_package,vcl,postprocess_images))
+endif
 
 # vim: set noet sw=4 ts=4: