Add a makefile to gumbo library

gumbo/Makefile

@@ -0,0 +1,9 @@
+SOURCES = attribute.c char_ref.c error.c parser.c string_buffer.c \
+	string_piece.c tag.c tokenizer.c utf8.c util.c vector.c
+
+libgumbo.a : $(SOURCES)
+	gcc -O2 -std=c99 -c  $(SOURCES)
+	ar -cvq libgumbo.a *.o
+
+clean:
+	rm *.o *.a