Merge pull request #1855 from alco/elixirappsrc

Mark the autogenerated lib/src/elixir.app.src as such

Author: José Valim

Makefile

@@ -43,7 +43,9 @@ compile: lib/elixir/src/elixir.app.src erlang elixir
 
 lib/elixir/src/elixir.app.src: src/elixir.app.src
 	$(Q) rm -rf lib/elixir/src/elixir.app.src
-	$(Q) cp src/elixir.app.src lib/elixir/src/elixir.app.src
+	$(Q) echo "%% This file is automatically generated from <project_root>/src/elixir.app.src" \
+	                             >lib/elixir/src/elixir.app.src
+	$(Q) cat src/elixir.app.src >>lib/elixir/src/elixir.app.src
 
 erlang:
 	$(Q) cd lib/elixir && $(REBAR) compile