all: quote string arguments in error messages

These strings are often file names or other user specified
parameters, which can give confusing errors in
the presence of unexpected characters for example.

* cfg.mk (sc_error_quotes): A new syntax check rule.
* src/*.c: Wrap error() string arguments with quote().
* tests/: Adjust accordingly.
* NEWS: Mention the improvement.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/du.c b/src/du.c
index 30378e552..0b405f47d 100644
--- a/src/du.c
+++ b/src/du.c
@@ -380,7 +380,7 @@ show_date (const char *format, struct timespec when)
     {
       char buf[INT_BUFSIZE_BOUND (intmax_t)];
       char *when_str = timetostr (when.tv_sec, buf);
-      error (0, 0, _("time %s is out of range"), when_str);
+      error (0, 0, _("time %s is out of range"), quote (when_str));
       fputs (when_str, stdout);
       return;
     }