Allow variable overrides in mmm and mmma

Change-Id: I12e8cc62e72d0af3b777f69727eafec9aa1713e3
diff --git a/envsetup.sh b/envsetup.sh
index 1bc14d5..d91b0b3 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -761,7 +761,7 @@
                 MAKEFILE="$MAKEFILE $MFILE"
             else
                 case $DIR in
-                  showcommands | snod | dist | incrementaljavac) ARGS="$ARGS $DIR";;
+                  showcommands | snod | dist | incrementaljavac | *=*) ARGS="$ARGS $DIR";;
                   GET-INSTALL-PATH) GET_INSTALL_PATH=$DIR;;
                   *) echo "No Android.mk in $DIR."; return 1;;
                 esac
@@ -817,7 +817,7 @@
         fi
       else
         case $DIR in
-          showcommands | snod | dist | incrementaljavac) ARGS="$ARGS $DIR";;
+          showcommands | snod | dist | incrementaljavac | *=*) ARGS="$ARGS $DIR";;
           *) echo "Couldn't find directory $DIR"; return 1;;
         esac
       fi