feature/pgtk aea5dbe: Fix DEL key behavior

[Yuuki Harano]

branch: feature/pgtk
commit aea5dbec2514811fb2e1cc44b2347a976a5b7de8
Author: Yuuki Harano <masm+github@masm11.me>
Commit: Yuuki Harano <masm+github@masm11.me>

    Fix DEL key behavior
    
    * lisp/simple.el (normal-erase-is-backspace-setup-frame): Include pgtk
    in window-system group.
---
 lisp/simple.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index d73bc6b..1f90db3 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -9180,7 +9180,7 @@ call `normal-erase-is-backspace-mode' (which see) 
instead."
        (if (if (eq normal-erase-is-backspace 'maybe)
                (and (not noninteractive)
                     (or (memq system-type '(ms-dos windows-nt))
-                       (memq window-system '(w32 ns))
+                       (memq window-system '(w32 ns pgtk))
                         (and (eq window-system 'x)
                              (fboundp 'x-backspace-delete-keys-p)
                              (x-backspace-delete-keys-p))