From 4e4441fd32e694753824a543c050e5d3c0b49a5a Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson@yhbt.net>
Date: Sat, 12 Apr 2008 04:16:22 +0000
Subject: configure: better CFLAGS checking

needed for compatibility with older gcc.  Also, threw in
some warnings for things I find offensive
(declaration-after-statement, shadow)

git-svn-id: https://svn.musicpd.org/mpd/trunk@7299 09075e82-0dd4-0310-85a5-a0d7c8717e4f
---
 configure.ac          | 12 ++++++++++--
 m4/mpd_check_cflag.m4 | 18 ++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 m4/mpd_check_cflag.m4

diff --git a/configure.ac b/configure.ac
index 1b8bc0400..81a94afdc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -10,6 +10,7 @@ AC_SUBST(MPD_CFLAGS)
 AC_SUBST(MP4FF_LIB)
 AC_SUBST(MP4FF_SUBDIR)
 
+AC_LANG(C)
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_PROG_INSTALL
@@ -21,8 +22,15 @@ AC_DEFINE(PROTOCOL_VERSION, "0.14.0", [The mpd protocol version])
 
 MPD_LIBS=""
 MPD_CFLAGS=""
-if test x$GCC = xyes; then
-	MPD_CFLAGS="-Wall -Wextra -Wno-unused-parameter -Wno-deprecated-declarations -Wmissing-prototypes"
+if test x$GCC = xyes
+then
+	MPD_CHECK_FLAG([-Wall])
+	MPD_CHECK_FLAG([-Wextra])
+	MPD_CHECK_FLAG([-Wno-unused-parameter])
+	MPD_CHECK_FLAG([-Wno-deprecated-declarations])
+	MPD_CHECK_FLAG([-Wmissing-prototypes])
+	MPD_CHECK_FLAG([-Wdeclaration-after-statement])
+	MPD_CHECK_FLAG([-Wshadow])
 fi
 
 if test -z "$prefix" || test "x$prefix" = xNONE; then
diff --git a/m4/mpd_check_cflag.m4 b/m4/mpd_check_cflag.m4
new file mode 100644
index 000000000..05682f611
--- /dev/null
+++ b/m4/mpd_check_cflag.m4
@@ -0,0 +1,18 @@
+AC_DEFUN([MPD_CHECK_FLAG],[
+  var=`echo "$1" | tr "-" "_"`
+  AC_CACHE_CHECK([whether the C compiler accepts $1],
+    [mpd_check_cflag_$var],[
+    save_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS $1"
+    AC_COMPILE_IFELSE([
+     int main(void) { return 0; }
+     ], [ eval "mpd_check_cflag_$var=yes"
+     ], [ eval "mpd_check_cflag_$var=no" ])
+    CFLAGS="$save_CFLAGS"
+  ])
+  if eval "test x`echo '$mpd_check_cflag_'$var` = xyes"
+  then
+    MPD_CFLAGS="$MPD_CFLAGS $1"
+  fi
+  ])
+])
-- 
cgit v1.2.3