+# check if compiler option is supported
+cc-supports = ${shell if $(CC) ${1} -S -o /dev/null -xc /dev/null > /dev/null 2>&1; then echo "$(1)"; fi;}
+
+WARNINGS := -Wall -fno-builtin -Wchar-subscripts -Wpointer-arith -Wstrict-prototypes -Wsign-compare
+WARNINGS += $(call cc-supports,-Wno-pointer-sign)
+WARNINGS += $(call cc-supports,-Wdeclaration-after-statement)