diff --git a/srcpkgs/upx/template b/srcpkgs/upx/template
index c562348651d..1505ea9d2b3 100644
--- a/srcpkgs/upx/template
+++ b/srcpkgs/upx/template
@@ -5,7 +5,7 @@ revision=1
 wrksrc="upx-${version}-src"
 build_style=gnu-makefile
 make_build_target=all
-make_build_args="CHECK_WHITESPACE=:"
+make_build_args="CHECK_WHITESPACE=: CXXFLAGS_WERROR="
 make_use_env=yes
 hostmakedepends="perl"
 makedepends="ucl zlib-devel"