diff --git a/srcpkgs/crossguid/fix-cflags.patch b/srcpkgs/crossguid/fix-cflags.patch
new file mode 100644
index 00000000000..983360a07cc
--- /dev/null
+++ b/srcpkgs/crossguid/fix-cflags.patch
@@ -0,0 +1,12 @@
+Index: CMakeLists.txt
+===================================================================
+--- CMakeLists.txt.orig
++++ CMakeLists.txt
+@@ -2,7 +2,6 @@ cmake_minimum_required(VERSION 3.5.1)
+ project(CrossGuid)
+ 
+ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake")
+-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
+ 
+ option(XG_TESTS "Build test runner" ON)
+