diff --git a/dev-cpp/ms-gsl/files/ms-gsl-0_pre20180304-disable_Werror-644042.patch b/dev-cpp/ms-gsl/files/ms-gsl-0_pre20180304-disable_Werror-644042.patch
new file mode 100644
index 0000000000000..9d2a43c223f34
--- /dev/null
+++ b/dev-cpp/ms-gsl/files/ms-gsl-0_pre20180304-disable_Werror-644042.patch
@@ -0,0 +1,27 @@
+From 402dd069acc1944428fd9f4ed3620a157028f6cc Mon Sep 17 00:00:00 2001
+From: Jan Henke <Jan.Henke@taujhe.de>
+Date: Sat, 17 Mar 2018 19:47:52 +0100
+Subject: [PATCH] Disable -Werror when compiling tests
+
+GCC 7 generates new warnings on some of the test files, which lead to
+build failures. -Werror generally is helpful while developing to enforce
+a zero error policy, but not so much when packaging. Gentoo bug 644042
+---
+ tests/CMakeLists.txt | 2 --
+ 1 file changed, 2 deletions(-)
+
+diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
+index 0e08d77..86e9af7 100644
+--- a/tests/CMakeLists.txt
++++ b/tests/CMakeLists.txt
+@@ -41,7 +41,6 @@ target_compile_options(gsl_tests_config INTERFACE
+         -Wcast-align
+         -Wconversion
+         -Wctor-dtor-privacy
+-        -Werror
+         -Wextra
+         -Wno-missing-braces
+         -Wnon-virtual-dtor
+-- 
+2.16.1
+
diff --git a/dev-cpp/ms-gsl/ms-gsl-0_pre20180304.ebuild b/dev-cpp/ms-gsl/ms-gsl-0_pre20180304.ebuild
index c80cd2a3517a3..34943ad4bf802 100644
--- a/dev-cpp/ms-gsl/ms-gsl-0_pre20180304.ebuild
+++ b/dev-cpp/ms-gsl/ms-gsl-0_pre20180304.ebuild
@@ -20,6 +20,7 @@ DEPEND="test? ( >=dev-cpp/catch-1.11.0 )"
 
 PATCHES=(
 	"${FILESDIR}/ms-gsl-0_pre20180108-use_system_catch-636828.patch"
+	"${FILESDIR}/ms-gsl-0_pre20180304-disable_Werror-644042.patch"
 )
 
 src_configure() {