Update to Makefile, added change notes.

Makefile

@@ -1,5 +1,15 @@
+# change notes:
+# 	filter out -Werror when compiling with gcc. It chooses to warn about strange things sometimes.
+# 	Compiles will all flags below on clang with -Werror.
+
 CC = gcc
-CFLAGS = -std=c11 -Wall -Wextra -Werror -O3 -g
+CFLAGS = -std=c11 -O3 -g -Wall -Wextra -Wformat=2 -Wshadow \
+		 -Wno-format-nonliteral -Wcast-align -Wwrite-strings -Wstrict-prototypes -Wold-style-definition \
+		 -Wredundant-decls -Wnested-externs -Wmissing-include-dirs -Wswitch-default
+
+ifneq ($(CC),gcc)
+	$(CFLAGS) += -Werror
+endif
 
 TESTS = $(wildcard tests/*.c)
 EXAMPLES = $(wildcard examples/*.c)