[glib] gstrfuncs: Clarify that g_strv_length() does not accept NULL

[Philip Withnall <pwithnall src gnome org>]

commit b806df0ef136b17251b01d962830f49301bbed0e
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Apr 10 11:04:07 2018 +0100

    gstrfuncs: Clarify that g_strv_length() does not accept NULL
    
    https://bugzilla.gnome.org/show_bug.cgi?id=795026
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    Reviewed-by: nobody

 glib/gstrfuncs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/glib/gstrfuncs.c b/glib/gstrfuncs.c
index e7240b612..a9889dd50 100644
--- a/glib/gstrfuncs.c
+++ b/glib/gstrfuncs.c
@@ -2882,7 +2882,7 @@ g_str_has_prefix (const gchar *str,
  * @str_array: a %NULL-terminated array of strings
  *
  * Returns the length of the given %NULL-terminated
- * string array @str_array.
+ * string array @str_array. @str_array must not be %NULL.
  *
  * Returns: length of @str_array.
  *