[vim/windows] Use chcp only if sed is in PATH

https://github.com/junegunn/vim-plug/pull/891

plugin/fzf.vim

@@ -50,14 +50,16 @@ if s:is_win
   " Use utf-8 for fzf.vim commands
   " Return array of shell commands for cmd.exe
   function! s:wrap_cmds(cmds)
+    let use_chcp = executable('sed')
     return map([
       \ '@echo off',
-      \ 'setlocal enabledelayedexpansion',
-      \ 'for /f "tokens=*" %%a in (''chcp'') do for %%b in (%%a) do set origchcp=%%b',
-      \ 'chcp 65001 > nul'
-    \ ]
+      \ 'setlocal enabledelayedexpansion']
+    \ + (use_chcp ? [
+      \ 'for /f "usebackq" %%a in (`chcp ^| sed "s/[^0-9]//gp"`) do set origchcp=%%a',
+      \ 'chcp 65001 > nul'] : [])
     \ + (type(a:cmds) == type([]) ? a:cmds : [a:cmds])
-    \ + ['chcp !origchcp! > nul', 'endlocal'],
+    \ + (use_chcp ? ['chcp !origchcp! > nul'] : [])
+    \ + ['endlocal'],
     \ 'v:val."\r"')
   endfunction
 else