(find_program): If argument contains a slash

(most likely because VPATH expansion in make), return the filename
as is.

Rev: misc/run-tests:1.5

run-tests

@@ -12,12 +12,21 @@ fi
 
 export srcdir
 
+# When used in make rules, we sometimes get the filenames VPATH
+# expanded, but usually not. 
 find_program () {
+    case "$1" in
+	*/*)
+	  echo "$1"
+	  ;;
+	*)
 	  if [ -x "$1" ] ; then
 	      echo "./$1"
 	  else
 	      echo "$srcdir/$1"
 	  fi
+	  ;;
+    esac
 }
 
 env_program () {