Add support with Go language.

sources_non_forked/vim-go/ftdetect/gofiletype.vim

@@ -0,0 +1,43 @@
+" vint: -ProhibitAutocmdWithNoGroup
+
+" don't spam the user when Vim is started in Vi compatibility mode
+let s:cpo_save = &cpo
+set cpo&vim
+
+" Note: should not use augroup in ftdetect (see :help ftdetect)
+au BufRead,BufNewFile *.go setfiletype go
+au BufRead,BufNewFile *.s setfiletype asm
+au BufRead,BufNewFile *.tmpl set filetype=gohtmltmpl
+au BufRead,BufNewFile go.sum set filetype=gosum
+au BufRead,BufNewFile go.work.sum set filetype=gosum
+au BufRead,BufNewFile go.work set filetype=gowork
+
+" remove the autocommands for modsim3, and lprolog files so that their
+" highlight groups, syntax, etc. will not be loaded. *.MOD is included, so
+" that on case insensitive file systems the module2 autocmds will not be
+" executed.
+au! BufRead,BufNewFile *.mod,*.MOD
+" Set the filetype if the first non-comment and non-blank line starts with
+" 'module <path>'.
+au BufRead,BufNewFile go.mod call s:gomod()
+
+fun! s:gomod()
+  for l:i in range(1, line('$'))
+    let l:l = getline(l:i)
+    if l:l ==# '' || l:l[:1] ==# '//'
+      continue
+    endif
+
+    if l:l =~# '^module .\+'
+      setfiletype gomod
+    endif
+
+    break
+  endfor
+endfun
+
+" restore Vi compatibility settings
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+" vim: sw=2 ts=2 et