xdialog: Fix building with recent GCC

Author: alarixnia

x11/xdialog/distinfo

@@ -6,3 +6,4 @@ Size (Xdialog-2.3.1.tar.bz2) = 457938 bytes
 SHA1 (patch-ac) = 785a6e5833617e0602699f8c7810a2db5c3354cf
 SHA1 (patch-ad) = f5d067838ce6418723fd0e7f658cea4442c88ce5
 SHA1 (patch-ae) = cc0759387ba3d23d4ef2eddcc46d51705b9a5714
+SHA1 (patch-configure) = f28498bde8d4f9cb189a777ef1da5d64072ad001

x11/xdialog/patches/patch-configure

@@ -0,0 +1,16 @@
+$NetBSD$
+
+Make sure the test for "ANSI C headers" actually conforms to ANSI C.
+
+Fixes build with modern GCC.
+
+--- configure.orig	2026-03-23 10:24:05.009456817 +0000
++++ configure
+@@ -5126,6 +5126,7 @@ _ACEOF
+ cat confdefs.h >>conftest.$ac_ext
+ cat >>conftest.$ac_ext <<_ACEOF
+ /* end confdefs.h.  */
++#include <stdlib.h>
+ #include <ctype.h>
+ #if ((' ' & 0x0FF) == 0x020)
+ # define ISLOWER(c) ('a' <= (c) && (c) <= 'z')