-# flag checks are grouped together to speed the checks up a bit..
-CFLAGS += $(call cc-option,-Wall -Wshadow -Wwrite-strings,)
-CFLAGS += $(call cc-option,-Wundef -Wstrict-prototypes,)
-# If you want to add "-Wmissing-prototypes -Wmissing-declarations" above
-# (or anything else for that matter) make sure that it is still possible
-# to build bbox without warnings. Current offender: find.c:alloc_action().
-# Looks more like gcc bug: gcc will warn on it with or without prototype.
-# But still, warning-free compile is a must, or else we will drown
-# in warnings pretty soon.
+CFLAGS += $(call cc-option,-Wall,)
+CFLAGS += $(call cc-option,-Wshadow,)
+CFLAGS += $(call cc-option,-Wwrite-strings,)
+CFLAGS += $(call cc-option,-Wundef,)
+CFLAGS += $(call cc-option,-Wstrict-prototypes,)
+CFLAGS += $(call cc-option,-Wunused -Wunused-parameter,)
+CFLAGS += $(call cc-option,-Wunused-function -Wunused-value,)
+CFLAGS += $(call cc-option,-Wmissing-prototypes -Wmissing-declarations,)
+CFLAGS += $(call cc-option,-Wno-format-security,)
+# warn about C99 declaration after statement
+CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
+# If you want to add more -Wsomething above, make sure that it is
+# still possible to build bbox without warnings.