diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 292fba760..5417a09e2 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1301,11 +1301,12 @@ endif()
 if( ZD_CMAKE_COMPILER_IS_GNUCXX_COMPATIBLE )
 	# Need to enable intrinsics for these files.
 	if( SSE_MATTERS )
-		set_source_files_properties(
+		set_property( SOURCE
 			rendering/polyrenderer/poly_all.cpp
 			rendering/swrenderer/r_all.cpp
+			utility/palette.cpp
 			utility/x86.cpp
-			PROPERTIES COMPILE_FLAGS "-msse2 -mmmx" )
+			APPEND_STRING PROPERTY COMPILE_FLAGS " -msse2 -mmmx" )
 	endif()
 endif()