diff --git a/CMakeLists.txt b/CMakeLists.txt
index d844617..7c6dbe9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,7 +25,7 @@ find_library(IOSURFACE_LIBRARY IOSurface REQUIRED)
 # Sources
 #
 set(SOURCE_FILES
-    src/mac.c
+    src/mac.m
     src/icon.icns
 )
 
diff --git a/src/mac.c b/src/mac.m
similarity index 100%
rename from src/mac.c
rename to src/mac.m