Add syntax files from upstream vim repository

compiler/dot.vim

@@ -0,0 +1,19 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim compiler file
+" Compiler:     ATT dot
+" Maintainer:	Marcos Macedo <bar4ka@bol.com.br>
+" Last Change:	2004 May 16
+
+if exists("current_compiler")
+  finish
+endif
+let current_compiler = "dot"
+
+if exists(":CompilerSet") != 2		" older Vim always used :setlocal
+  command -nargs=* CompilerSet setlocal <args>
+endif
+
+CompilerSet makeprg=dot\ -T$*\ \"%:p\"\ -o\ \"%:p:r.$*\"
+
+endif