diff --git a/usr/include/Makefile b/usr/include/Makefile
index a339ef325aa5..b568a95d1f62 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -93,7 +93,7 @@ no-header-test += asm-generic/%
 
 extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
 
-# Include the header to detect missing include guard.
+# Include the header twice to detect missing include guard.
 quiet_cmd_hdrtest = HDRTEST $<
       cmd_hdrtest = \
 		$(CC) $(c_flags) -S -o /dev/null -x c /dev/null \