iproute2: fix broken configuration patch

Since v4.13, iproute2 switched to a config.mk file with greater use of
pkg-config for library/feature detection. Replace the old Config patch
with one modifying the configure script but enabling the same changes:
 - explicitly disable TC_CONFIG_ATM
 - rely on feature detection for IP_CONFIG_SETNS and TC_CONFIG_XT

Signed-off-by: Tony Ambardar <itugrok@yahoo.com>

package/network/utils/iproute2/patches/100-config.patch

@@ -1,7 +0,0 @@
---- /dev/null
-+++ b/Config
-@@ -0,0 +1,4 @@
-+# Fixed config to disable ATM support even if present on host system
-+IP_CONFIG_SETNS:=y
-+TC_CONFIG_ATM:=n
-+TC_CONFIG_XT:=y

package/network/utils/iproute2/patches/100-configure.patch

@@ -0,0 +1,12 @@
+--- a/configure
++++ b/configure
+@@ -32,7 +32,8 @@ int main(int argc, char **argv) {
+ }
+ EOF
+ 
+-    if $CC -I$INCLUDE -o $TMPDIR/atmtest $TMPDIR/atmtest.c -latm >/dev/null 2>&1; then
++# OpenWrt: disable ATM support even if present on host system
++    if [ 1 -eq 0 ]; then
+ 	echo "TC_CONFIG_ATM:=y" >>$CONFIG
+ 	echo yes
+     else