From d9cd05188a20515f02087ef95d7c2a06dc41d4e2 Mon Sep 17 00:00:00 2001
From: Erik de Castro Lopo <erikd@mega-nerd.com>
Date: Mon, 20 Jul 2015 20:29:42 +1000
Subject: Add -Wall to CFLAGS if compiler supports it

---
 configure.ac     |  2 ++
 m4/add_cflags.m4 | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 m4/add_cflags.m4

diff --git a/configure.ac b/configure.ac
index b4594e2..c4b357e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -304,6 +304,8 @@ case $SIZEOF32 in
     $ac_cv_sizeof_long) USIZE32="unsigned long";;
 esac
 
+XIPH_ADD_CFLAGS([-Wall])
+
 AS_IF([test -z "$SIZE16"],[AC_MSG_ERROR([No 16 bit type found on this platform!])])
 AS_IF([test -z "$SIZE32"],[AC_MSG_ERROR([No 32 bit type found on this platform!])])
 AS_IF([test -z "$USIZE16"],[AC_MSG_ERROR([No unsigned 16 bit type found on this platform!])])
diff --git a/m4/add_cflags.m4 b/m4/add_cflags.m4
new file mode 100644
index 0000000..08f4a40
--- /dev/null
+++ b/m4/add_cflags.m4
@@ -0,0 +1,18 @@
+dnl @synopsis XIPH_ADD_CFLAGS
+dnl
+dnl Add the given option to CFLAGS, if it doesn't break the compiler
+
+AC_DEFUN([XIPH_ADD_CFLAGS],
+[AC_MSG_CHECKING([if $CC accepts $1])
+	ac_add_cflags__old_cflags="$CFLAGS"
+	CFLAGS="$1"
+	AC_TRY_LINK([
+			#include <stdio.h>
+			],
+		[puts("Hello, World!"); return 0;],
+		AC_MSG_RESULT([yes])
+			CFLAGS="$ac_add_cflags__old_cflags $1",
+		AC_MSG_RESULT([no])
+			CFLAGS="$ac_add_cflags__old_cflags"
+		)
+])# XIPH_ADD_CFLAGS
-- 
cgit v1.2.3