Some windows fixes.

environment.py

@@ -62,7 +62,7 @@ class CCompiler():
     def split_shlib_to_parts(self, fname):
         return (None, fname)
 
-    def build_rpath_arg(self, build_dir, rpath_paths):
+    def build_rpath_args(self, build_dir, rpath_paths):
         return []
 
     def get_id(self):
@@ -662,6 +662,9 @@ class VisualStudioLinker():
     def get_always_flags(self):
         return VisualStudioLinker.always_flags
 
+    def build_rpath_args(self, build_dir, rpath_paths):
+        return []
+
 class ArLinker():
     std_flags = ['csr']
 
@@ -685,6 +688,7 @@ class ArLinker():
 
     def get_always_flags(self):
         return []
+
 def exe_exists(arglist):
     try:
         p = subprocess.Popen(arglist, stdout=subprocess.PIPE, stderr=subprocess.PIPE)