gen_makefile: tweak edit detector

Change-Id: I6a1753e24b29226894fdfcac8132910501a633b8
diff --git a/gen_makefile.py b/gen_makefile.py
index 5af7803..05db443 100755
--- a/gen_makefile.py
+++ b/gen_makefile.py
@@ -153,7 +153,7 @@
 
 .PHONY: .make.{proj}.detect_edits
 .make.{proj}.detect_edits:
-	@test -z "$(shell find {src_proj} -newer .make.{proj}.last_edited -name "*.[hc]")" || (touch .make.{proj}.last_edited; echo {proj} edited)
+	@test -z "$(shell find {src_proj} -newer .make.{proj}.last_edited -name "*.[hc]"  '(' -name "*.[hc]" -or -name "Makefile.am" -or -name "*.py" ')' )" || (touch .make.{proj}.last_edited; echo {proj} edited)
 
 .make.{proj}.build: .make.{proj}.configure .make.{proj}.last_edited
 	@echo "\n\n\n===== $@\n"