python3: fix builtins imports

The intent of this code is to generate things like -L=/usr/lib/foo so
for paths which start with "/" we should appent the "=". We should not do this
for ".". On some recent versions of binutils or patchsets on some recent
distros this appears to work differently and causes build failures, for example
on Ubuntu 14.04 LTS.

The simple fix is to check for "." as the path prefix.

[YOCTO #6467].

(From OE-Core rev: c36d459f0d40bdbd3ba809835e0475e8992bc778)

Signed-off-by: Roxana <roxana.ciobanu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python3/unixccompiler.patch

@@ -13,11 +13,13 @@ Index: Python-3.3.2/Lib/distutils/unixccompiler.py
 ===================================================================
 --- Python-3.3.2.orig/Lib/distutils/unixccompiler.py	2013-05-15 09:32:54.000000000 -0700
 +++ Python-3.3.2/Lib/distutils/unixccompiler.py	2013-08-01 00:58:18.629056286 -0700
-@@ -202,7 +202,7 @@
+@@ -202,7 +202,9 @@
      # ccompiler.py.
  
      def library_dir_option(self, dir):
 -        return "-L" + dir
++        if dir.startswith("."):
++            return "-L" + dir
 +        return "-L=" + dir
  
      def _is_gcc(self, compiler_name):