add notes

quad/library.mk

@@ -14,6 +14,8 @@ TESTOBJECTS = $(patsubst $.c, %.o, $(TESTSOURCES))
 
 TARGET = $(LIBDIR)/lib$(NAME).a
 TESTBIN = run_tests
+
+# For Unity; allows custom configuration
 UNITYDEFINES = -DUNITY_INCLUDE_CONFIG_H
 
 .PHONY: default test clean