buggy configure, add support for -L, as clang will not link with /usr/local

by default.

(patch sent to upstream)

security/botan2/patches/patch-configure_py

@@ -1,7 +1,16 @@
-$OpenBSD: patch-configure_py,v 1.2 2017/04/10 11:10:33 bluhm Exp $
---- configure.py.orig	Wed Apr  5 03:09:22 2017
-+++ configure.py	Fri Apr  7 22:40:26 2017
-@@ -2465,10 +2465,6 @@ def main(argv=None):
+$OpenBSD: patch-configure_py,v 1.3 2017/05/12 23:47:57 espie Exp $
+Index: configure.py
+--- configure.py.orig
++++ configure.py
+@@ -989,6 +989,7 @@ class CompilerInfo(InfoObject): # pylint: disable=too-
+         self.add_framework_option = lex.add_framework_option
+         self.add_include_dir_option = lex.add_include_dir_option
+         self.add_lib_option = lex.add_lib_option
++        self.add_lib_dir_option = lex.add_lib_dir_option
+         self.ar_command = lex.ar_command
+         self.binary_link_commands = force_to_dict(lex.binary_link_commands)
+         self.binary_name = lex.binary_name
+@@ -2465,10 +2466,6 @@ def main(argv=None):
              if have_program('clang++'):
                  options.compiler = 'clang'
          elif options.os == 'openbsd':