diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
index e6e927b60..34b3fa6c2 100644
--- a/externals/CMakeLists.txt
+++ b/externals/CMakeLists.txt
@@ -56,7 +56,8 @@ endif()
 
 # Sirit
 # Tell sirit to use our target
-set(SIRIT_USE_SYSTEM_SPIRV_HEADERS OFF)
+set(SIRIT_USE_SYSTEM_SPIRV_HEADERS ON)
+list(APPEND CMAKE_PREFIX_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 add_subdirectory(sirit)
 
 # SPIRV-Tools