makefile revised (and simplified)
makefile revised (and simplified)

arshiacont/libmusicxml,grame-cncm/libmusicxml,dfober/libmusicxml,arshiacont/libmusicxml,arshiacont/libmusicxml,dfober/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml,grame-cncm/libmusicxml,grame-cncm/libmusicxml,arshiacont/libmusicxml,dfober/libmusicxml,grame-cncm/libmusicxml,arshiacont/libmusicxml,grame-cncm/libmusicxml