diff --git a/contrib/src/png/rules.mak b/contrib/src/png/rules.mak
index 84481c9feb92b7cab259d2f3a4e5b72b03ac539c..ac4c61c237411165fa6a26b3cf567744c275880c 100644
--- a/contrib/src/png/rules.mak
+++ b/contrib/src/png/rules.mak
@@ -29,9 +29,7 @@ PNG_CONF += -DCMAKE_ASM_FLAGS="$(CFLAGS)"
 endif
 endif
 
-ifdef HAVE_WIN32
 PNG_CONF += -DPNG_DEBUG_POSTFIX:STRING=
-endif
 
 ifeq ($(ARCH),arm)
 ifdef HAVE_IOS