move the rtnetlink.h/C99 check and always fail configure if it fails

diff --git a/configure.ac b/configure.ac
index 31bda448269b33c831f2dd94b4f0cdf7f564e810..a055f7ae700d485d0b972233bac3d223875c06d4 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -143,6 +143,15 @@ AC_DEFINE([HAVE_NETLINK],[],[Support for Linux netlink])
 
 AM_CONDITIONAL(HAVE_NETLINK, [ test x"$HAVE_NETLINK" = xyes ])
 
+if test "x$HAVE_NETLINK" = "xyes" ; then
+    # Test whether rtnetlink.h can be included when compiled with -std=c99
+    # some distributions (e.g. archlinux) have broken headers that dont
+    # define __u64 with -std=c99
+    AC_MSG_CHECKING([checking whether rtnetlink.h can be included with -std=c99])
+    AC_TRY_COMPILE([#include <linux/rtnetlink.h>], [],
+        [AC_MSG_RESULT([yes])], [AC_MSG_ERROR([no])])
+fi
+
 #
 # Check for net/route.h
 #
@@ -238,28 +247,6 @@ if test "x$GCC" = "xyes" ; then
 
     DESIRED_FLAGS="-Wall -W -Wextra -pedantic -pipe -Wformat -Wold-style-definition -Wdeclaration-after-statement -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wendif-labels -Wpointer-arith -Wbad-function-cast -Wcast-qual -Wcast-align -Wwrite-strings -fdiagnostics-show-option -Wno-cast-qual -fno-strict-aliasing"
 
-    if test "x$HAVE_NETLINK" = "xyes" ; then
-        # Test whether rtnetlink.h can be included when compiled with -std=c99
-        # some distributions (e.g. archlinux) have broken headers that dont
-        # define __u64 with -std=c99
-        AC_MSG_CHECKING([checking whether rtnetlink.h can be included with -std=c99])
-        OLDCFLAGS="$CFLAGS"
-        CFLAGS="-std=c99"
-        AC_TRY_COMPILE([#include <linux/rtnetlink.h>], [],
-            use_stdc99=yes, use_stdc99=no)
-
-        if test x"$use_stdc99" = xyes; then
-            DESIRED_FLAGS="-std=c99 $DESIRED_FLAGS"
-            AC_MSG_RESULT([yes])
-        else
-            AC_MSG_RESULT([no])
-        fi
-
-        CFLAGS="$OLDCFLAGS"
-    else
-        DESIRED_FLAGS="-std=c99 $DESIRED_FLAGS"
-    fi
-
     for flag in $DESIRED_FLAGS ; do
         AC_MSG_CHECKING([whether $CC accepts $flag])
         if test_gcc_flag $flag ; then