Cleanup Makefile

Change-Id: I8b8d23b77e0f464fab64dff6431f738cded30b2a
diff --git a/Makefile b/Makefile
index f207d68..d376760 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,16 @@
-DIRS = $(filter %/, $(wildcard */))
+DIRS := $(wildcard */.)
 
-COMMANDS = distro source-build build dput clean
+COMMANDS := distro source-build build dput clean
 
-all:
+all: help
+
+help:
 	@echo "Available commands:"
 	@\
-for command in ${COMMANDS}; do  \
-echo "  $$command"; \
+for command in ${COMMANDS}; do \
+  echo "  $$command"; \
 done
 
-
 $(COMMANDS): ${DIRS}
 	@\
 for dir in ${DIRS}; do \
@@ -23,3 +24,4 @@
   (cd $$dir && $(MAKE) build && cp work/*.deb ../.deb/) ; \
 done
 
+.PHONY: all help deb