-DEBUG_CPPFLAGS += -Wno-sign-compare -g -Wunused -Wundef -W
-DEBUG_CPPFLAGS += -Wredundant-decls
-CPPFLAGS += -Os
-CPPFLAGS += -Wall
-CPPFLAGS += -Wuninitialized
-CPPFLAGS += -Wchar-subscripts
-CPPFLAGS += -Wformat-security
-CPPFLAGS += -Werror-implicit-function-declaration
-CPPFLAGS += -Wmissing-format-attribute
-CPPFLAGS += -Wunused-macros
-CPPFLAGS += -Wbad-function-cast
+DEBUG_CFLAGS ?=
+DEBUG_CFLAGS += -Wno-sign-compare -g -Wunused -Wundef
+DEBUG_CFLAGS += -Wredundant-decls
+CFLAGS ?=
+CFLAGS += -Os
+CFLAGS += -Wall
+CFLAGS += -Wuninitialized
+CFLAGS += -Wchar-subscripts
+CFLAGS += -Wformat-security
+CFLAGS += -Werror-implicit-function-declaration
+CFLAGS += -Wmissing-format-attribute
+CFLAGS += -Wunused-macros
+CFLAGS += -Wunused-parameter
+CFLAGS += -Wbad-function-cast
+CFLAGS += -Wshadow