diff --git a/tool/ifchange b/tool/ifchange
index 396a7a0bcf..050c8d8f26 100755
--- a/tool/ifchange
+++ b/tool/ifchange
@@ -31,6 +31,9 @@ until [ $# -eq 0 ]; do
 	--color=*)
 	    color=`expr \( "$1" : '[^=]*=\(.*\)' \)`
 	    ;;
+	--debug)
+	    set -x
+	    ;;
 	*)
 	    break
 	    ;;
diff --git a/win32/ifchange.bat b/win32/ifchange.bat
index f7ed58ffa5..606d6ed66e 100755
--- a/win32/ifchange.bat
+++ b/win32/ifchange.bat
@@ -35,6 +35,10 @@ if "%opt%" == "--timestamp" (
     set color=%opt:~8%
     shift
     goto :optloop
+) else if "%opt%" == "--debug" (
+    shift
+    echo on
+    goto :optloop
 )
 if "%opt%" == "" goto :end