commit e18a9f1429efc0aff81d06fbaffcc44ce2c1d7b2
from: Omar Polo <op@omarpolo.com>
date: Mon Mar 15 19:24:47 2021 UTC

add various -W flags

commit - 740f578bf26b43ced66468985fa8c84e862b2a9d
commit + e18a9f1429efc0aff81d06fbaffcc44ce2c1d7b2
blob - b9b28e298ff8e90a9b8f269d04512a380ae550e5
blob + 5c8d2187a97b6002a08ac45a907bc7f907fff67b
--- configure.ac
+++ configure.ac
@@ -40,6 +40,23 @@ AC_CHECK_LIB(util, imsg_init, [], [
 	AC_LIBOBJ(imsg-buffer)
 ])
 
+# check compiler flags
+AC_DEFUN([CC_ADD_CHECK_FLAGS], [
+	AC_MSG_CHECKING([if $CC supports $1 flag])
+	old_CFLAGS="$CFLAGS"
+	CFLAGS="$CFLAGS $1"
+	AC_COMPILE_IFELSE([AC_LANG_PROGRAM([],[])],
+		AC_MSG_RESULT(yes),
+		AC_MSG_RESULT(no)
+		CFLAGS="$old_CFLAGS")
+])
+CC_ADD_CHECK_FLAGS([-Wall])
+CC_ADD_CHECK_FLAGS([-Wextra])
+CC_ADD_CHECK_FLAGS([-Wmissing-prototypes])
+CC_ADD_CHECK_FLAGS([-Wstrict-prototypes])
+CC_ADD_CHECK_FLAGS([-Wwrite-strings])
+CC_ADD_CHECK_FLAGS([-Wno-unused-parameter])
+
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([
 	Makefile