diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9a8534d..07422e8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -98,6 +98,10 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   list(APPEND TEST_FLAGS -Wno-gnu-anonymous-struct -Wno-nested-anon-types)
 endif()
 
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
+  list(APPEND TEST_FLAGS -fms-extensions)
+endif()
+
 include(CTest)
 
 if(BUILD_TESTING)