tools: checkpatch updated with darr_foreach iter macros

Also update `checkpatch.sh` so it runs `checkpatch.pl` from the same directory
it resides in. This allows copying them both somewhere else to use a specific
version.

Signed-off-by: Christian Hopps <chopps@labn.net>

tools/checkpatch.pl

@@ -547,7 +547,7 @@ sub hash_show_words {
 
 our $c90_Keywords = qr{do|for|while|if|else|return|goto|continue|switch|default|case|break}x;
 our $Iterators	= qr{
-			frr_each|frr_each_safe|frr_each_from|
+			darr_foreach_p|darr_foreach_i|frr_each|frr_each_safe|frr_each_from|
 			frr_with_mutex|frr_with_privs|
 			LIST_FOREACH|LIST_FOREACH_SAFE|
 			SLIST_FOREACH|SLIST_FOREACH_SAFE|SLIST_FOREACH_PREVPTR|

tools/checkpatch.sh

@@ -3,7 +3,8 @@
 usage="./checkpatch.sh <patch> <tree>"
 patch=$1
 tree=$2
-checkpatch="$tree/tools/checkpatch.pl --no-tree -f"
+scriptdir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd)"
+checkpatch="$scriptdir/checkpatch.pl --no-tree -f"
 ignore="ldpd\|babeld"
 cwd=${PWD##*/}
 dirty=0