gh-126877: Fix the configure check for Tcl/Tk with optimizing compilers#153543
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…ompilers 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. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15. |
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GH-153553 is a backport of this pull request to the 3.15 branch. |
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GH-153554 is a backport of this pull request to the 3.14 branch. |
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GH-153555 is a backport of this pull request to the 3.13 branch. |
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…compilers (GH-153543) (GH-153555) 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 ff0a9ae) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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…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 ff0a9ae) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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…compilers (GH-153543) (GH-153553) 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 ff0a9ae) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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…ompilers (pythonGH-153543) 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. Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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The
configurecheck for Tcl/Tk assigned the addresses ofTcl_Init()andTk_Init()to unused variables. Optimizing compilers can eliminate these dead stores, dropping the only reference to the symbols, so the check links — and Tcl/Tk is detected as available — even when the libraries are missing.This calls the functions instead, matching the existing
__register_frame()probe in the same file. A call to an external function cannot be optimized away, and the check still only links and never runs, so it stays cross-compile safe.Verified with gcc at
-O2: the old probe links with the symbols absent, the new one correctly fails, andconfigurethen reports_tkinter... missinginstead of a false positive.