configure: add filter_out() function

This adds a function to filter out words matching a pattern
from a list.
Signed-off-by: NMans Rullgard <mans@mansr.com>

configure

@@ -321,6 +321,14 @@ filter(){
     done
 }
 
+filter_out(){
+    pat=$1
+    shift
+    for v; do
+        eval "case $v in $pat) ;; *) echo $v ;; esac"
+    done
+}
+
 map(){
     m=$1
     shift