Invalidate the tag_files.tfd after fclose(3)ing the stram associated

with it.  In main() assert that the tfd was actually invalidated.
This avoids closing an invalid fd.
From tb@; OK deraadt@ on an earlier version.

1 files changed, 1 insertions, 1 deletions

diff --git a/main.c b/main.c
index 308f7fb5..f7c15494 100644
--- a/main.c
+++ b/main.c
@@ -1184,7 +1184,7 @@ spawn_pager(struct tag_files *tag_files)
 	if (dup2(tag_files->ofd, STDOUT_FILENO) == -1)
 		err((int)MANDOCLEVEL_SYSERR, "pager stdout");
 	close(tag_files->ofd);
-	close(tag_files->tfd);
+	assert(tag_files->tfd == -1);
 
 	/* Do not start the pager before controlling the terminal. */