[gtksourceview] implregex: make start_pos have sign bit

[Christian Hergert <chergert src gnome org>]

commit a44df04bc7b17c1175a3e183940f4b1db3ac36a3
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jul 2 14:28:27 2021 -0700

    implregex: make start_pos have sign bit

 gtksourceview/implregex.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtksourceview/implregex.c b/gtksourceview/implregex.c
index ac64750b..a18b1fbb 100644
--- a/gtksourceview/implregex.c
+++ b/gtksourceview/implregex.c
@@ -75,7 +75,7 @@ struct _ImplMatchInfo
        pcre2_match_data *match_data;
        PCRE2_SIZE       *offsets;
        int               matches;
-       gsize             start_pos;
+       gssize            start_pos;
 };
 
 static gsize