From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Sat, 11 Jul 2026 10:08:13 +0000 (+0200)
Subject: [3.14] gh-126877: Fix the configure check for Tcl/Tk with optimizing compilers (GH... 
X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;h=ec42ea44d2508a3e39e19b7bdc351434c84ab70c;p=thirdparty%2FPython%2Fcpython.git

[3.14] gh-126877: Fix the configure check for Tcl/Tk with optimizing compilers (GH-153543) (GH-153554)

The check assigned the addresses of Tcl_Init() and Tk_Init() to unused
variables, which optimizing compilers can eliminate, so it linked even
when the libraries were missing.  Call the functions instead.
(cherry picked from commit ff0a9ae269fa38c21f01bdea1a7ff5d439c4f681)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
---

diff --git a/Misc/NEWS.d/next/Build/2026-07-11-07-26-16.gh-issue-126877.Zt7Kq2.rst b/Misc/NEWS.d/next/Build/2026-07-11-07-26-16.gh-issue-126877.Zt7Kq2.rst
new file mode 100644
index 000000000000..1d7d4fad886c
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2026-07-11-07-26-16.gh-issue-126877.Zt7Kq2.rst
@@ -0,0 +1,2 @@
+Fix the :program:`configure` check for Tcl/Tk which could wrongly succeed
+with optimizing compilers when the libraries are missing.
diff --git a/configure b/configure
index 8c6bf8b3cfe4..717a20791241 100755
--- a/configure
+++ b/configure
@@ -17322,8 +17322,8 @@ int
 main (void)
 {
 
-      void *x1 = Tcl_Init;
-      void *x2 = Tk_Init;
+      Tcl_Init(NULL);
+      Tk_Init(NULL);
 
   ;
   return 0;
diff --git a/configure.ac b/configure.ac
index a65c16a05b15..cac2f931c91a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4544,8 +4544,8 @@ WITH_SAVE_ENV([
       #  error "Tk older than 8.5.12 not supported"
       #endif
     ], [
-      void *x1 = Tcl_Init;
-      void *x2 = Tk_Init;
+      Tcl_Init(NULL);
+      Tk_Init(NULL);
     ])
   ], [
     have_tcltk=yes