From 1e48bdb45bba9fa7cad7cf93a7f50647d467d2b7 Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Mon, 28 Sep 2020 15:49:11 -0700
Subject: [PATCH] Avoid implicit declaration of function 'RB_OBJ_UNTRUST' in
 Ruby 3

Starting in 2.7, there is no reason to taint/untrust, so just
make RbTk_OBJ_UNTRUST a no-op in Ruby 2.7+.
---
 ext/tk/extconf.rb | 2 ++
 ext/tk/tcltklib.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/ext/tk/extconf.rb b/ext/tk/extconf.rb
index d798c110..8e5fb254 100644
--- a/ext/tk/extconf.rb
+++ b/ext/tk/extconf.rb
@@ -5,6 +5,8 @@
 ##############################################################
 require 'mkmf'
 
+$CFLAGS << " -DNO_TAINT" if RUBY_VERSION >= '2.7'
+
 TkLib_Config = {}
 TkLib_Config['search_versions'] =
   # %w[8.9 8.8 8.7 8.6 8.5 8.4 8.3 8.2 8.1 8.0 7.6 4.2]
diff --git a/ext/tk/tcltklib.c b/ext/tk/tcltklib.c
index f6b2793a..fe5bae97 100644
--- a/ext/tk/tcltklib.c
+++ b/ext/tk/tcltklib.c
@@ -46,11 +46,15 @@ int rb_thread_check_trap_pending(void);
 #define RARRAY_AREF(a, i) RARRAY_CONST_PTR(a)[i]
 #endif
 
+#ifdef NO_TAINT
+#define RbTk_OBJ_UNTRUST(x)  do {} while (0)
+#else
 #ifdef OBJ_UNTRUST
 #define RbTk_OBJ_UNTRUST(x)  do {OBJ_TAINT(x); OBJ_UNTRUST(x);} while (0)
 #else
 #define RbTk_OBJ_UNTRUST(x)  OBJ_TAINT(x)
 #endif
+#endif
 #define RbTk_ALLOC_N(type, n) (type *)ckalloc((int)(sizeof(type) * (n)))
 
 #if defined(HAVE_RB_PROC_NEW) && !defined(RUBY_VM)