Ignore trailing slashes

Author: Sascha Schumann

acinclude.m4

@@ -476,7 +476,7 @@ AC_DEFUN(AC_EXPAND_PATH,[
     $2="$1"
   else
     changequote({,})
-    ep_dir="`echo $1|sed 's%/*[^/][^/]*$%%'`"
+    ep_dir="`echo $1|sed 's%/*[^/][^/]*/*$%%'`"
     changequote([,])
     ep_realdir="`(cd \"$ep_dir\" && pwd)`"
     $2="$ep_realdir/`basename \"$1\"`"