Add syntax files from upstream vim repository

compiler/msvc.vim

@@ -0,0 +1,17 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim compiler file
+" Compiler:	Microsoft Visual C
+" Maintainer:	Bram Moolenaar <Bram@vim.org>
+" Last Change:	2014 Sep 20
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "msvc"
+
+" The errorformat for MSVC is the default.
+CompilerSet errorformat&
+CompilerSet makeprg=nmake
+
+endif