A patch from Larry to fix pristine source builds (again).

I just can't seem to _not_ break it.  Sigh.

applets/busybox.sh

@@ -9,7 +9,7 @@ RAW=` \
     | tr A-Z a-z | sort
 `
 test "${RAW}" != "" ||  exit
-cd ${2:-.}
+if [ -d $BB_SRC_DIR ]; then cd $BB_SRC_DIR; fi
 # By running $RAW through "ls", we avoid listing
 # source files that don't exist.
 ls $RAW 2>/dev/null | tr '\n' ' '