[vte] widget: Fix assertion failure in vte_terminal_event_check_regex_array

[Christian Persch <chpe src gnome org>]

commit eae447e4d22a073bb7cac2ff6937f43747ccbee0
Author: Christian Persch <chpe src gnome org>
Date:   Wed Apr 29 13:13:40 2020 +0200

    widget: Fix assertion failure in vte_terminal_event_check_regex_array
    
    Simply return NULL when n_regexes is 0.
    
    https://gitlab.gnome.org/GNOME/vte/-/issues/228#note_783787

 src/vtegtk.cc | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 4c0fd1b0..e95702b1 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -2292,6 +2292,9 @@ vte_terminal_event_check_regex_array(VteTerminal *terminal,
                                      guint32 match_flags,
                                      gsize *n_matches)
 {
+        if (n_regexes == 0)
+                return nullptr;
+
         auto matches = vte::glib::take_free_ptr(g_new0(char*, n_regexes));
         if (!vte_terminal_event_check_regex_simple(terminal,
                                                    event,