runtime(c): only set keywordprg when there has 'man'

closes: #19319

Signed-off-by: Mao-Yining <mao.yining@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

diff --git a/runtime/ftplugin/c.vim b/runtime/ftplugin/c.vim
index 2793c5d46ad9739b1ddf94d77e52aae08d82cc6f..97111121c31e5812bf386841eb7bb9c744edc3e6 100644 (file)
--- a/runtime/ftplugin/c.vim
+++ b/runtime/ftplugin/c.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin file
 " Language:    C
 " Maintainer:  The Vim Project <https://github.com/vim/vim>
-" Last Change: 2026 Jan 26
+" Last Change: 2026 Feb 3
 " Former Maintainer:   Bram Moolenaar <Bram@vim.org>
 
 " Only do this when not done yet for this buffer
@@ -41,7 +41,7 @@ if has("vms")
 endif
 
 " Use terminal window for gui
-if has('gui_running') && exists(':terminal') == 2
+if has('gui_running') && exists(':terminal') == 2 && executable("man")
   setlocal keywordprg=:CKeywordPrg
 
   command! -buffer -nargs=1 -count CKeywordPrg call s:CKeywordPrg(<q-args>, <count>)