sim: added makefile.sources to the list of dependencies for the simulation

changing makefile.sources did not restart the modelsim project setup
process. I added makefile.sources to the list of dependencies.

sim/makefile

@@ -26,7 +26,7 @@ mproject : mproject_created
 
 
 # The real target should be the .mpf file that is modified in each compilation/simulation
-mproject_created : $(SOURCE_FILES)
+mproject_created : $(SOURCE_FILES) makefile.sources
 	# create modelsim project
 	rm -rf ./modelsim_sources.tcl
 	for source_file in $(SOURCE_FILES); do \