Merge branch 'jk/test-without-readlink-1'

Some test scripts assumed that readlink(1) was universally
installed and available, which is not the case.

* jk/test-without-readlink-1:
  t: use portable wrapper for readlink(1)

t/test-lib-functions.sh

@@ -1708,3 +1708,9 @@ test_region () {
 
 	return 0
 }
+
+# Print the destination of symlink(s) provided as arguments. Basically
+# the same as the readlink command, but it's not available everywhere.
+test_readlink () {
+	perl -le 'print readlink($_) for @ARGV' "$@"
+}