games-engines/stratagus: Strip -Werror

Closes: https://bugs.gentoo.org/756142
Signed-off-by: Michał Górny <mgorny@gentoo.org>

games-engines/stratagus/stratagus-2.4.3.ebuild

@@ -42,6 +42,11 @@ PATCHES=(
 	"${FILESDIR}/${PN}"-2.3.0-doc.patch
 )
 
+src_prepare() {
+	sed -i -e 's:-Werror::' CMakeLists.txt || die
+	cmake_src_prepare
+}
+
 src_configure() {
 	# there are in-source switches
 	use debug && CMAKE_BUILD_TYPE=Debug