Adds support for the library_dirs key, which appears in the documentation but was never actually im…

pylib/gyp/generator/make.py

Index: pylib/gyp/generator/make.py
===================================================================
--- pylib/gyp/generator/make.py	(revision 1656)
+++ pylib/gyp/generator/make.py	(working copy)
@@ -1425,6 +1425,8 @@
             ldflags.append(r'-Wl,-rpath=\$$ORIGIN/lib.%s/' % self.toolset)
             ldflags.append(r'-Wl,-rpath-link=\$(builddir)/lib.%s/' %
                            self.toolset)
+        library_dirs = config.get('library_dirs', [])
+        ldflags += [('-L%s' % library_dir) for library_dir in library_dirs]
         self.WriteList(ldflags, 'LDFLAGS_%s' % configname)
         if self.flavor == 'mac':
           self.WriteList(self.xcode_settings.GetLibtoolflags(configname),