ifchange: --debug option

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62300 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/ifchange

@@ -31,6 +31,9 @@ until [ $# -eq 0 ]; do
 	--color=*)
 	    color=`expr \( "$1" : '[^=]*=\(.*\)' \)`
 	    ;;
+	--debug)
+	    set -x
+	    ;;
 	*)
 	    break
 	    ;;

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