diff --git a/CMakeLists.txt b/CMakeLists.txt
index 42a9ebd..fd80f78 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -183,7 +183,8 @@
 
 # source files to be covered by the 'format' target
 set(format_sources
-    compat/*
+    compat/*.c
+    compat/*.h
     src/*.c
     src/*.h
     src/plugins_exts/*