gh-131372: Include LDVERSION and EXE in base_interpreter value

[befeleme]

When looking at #131372 with @encukou we've realized there could be an easy fix to the first issue described there.

In Fedora, build-details.json created and installed for python3.14t contains "/usr/bin/python3.14" as the base_interpreter value. Create a correct string, taking into account both LDVERSION and EXE config variables, similarly to how it's defined in altbininstall in Makefile.

cpython/Makefile.pre.in

Line 2448 in 1a7824a

(cd $(DESTDIR)$(BINDIR); $(LN) python$(LDVERSION)$(EXE) python$(VERSION)$(EXE)); \

• Issue: build-details.json should be installed to different locations for nondebug/debug builds and have distinct base_interpreter values #131372

[vstinner]

This change alone doesn't work, since Free Threading or Debug Build would override build-details.json installed by the regular Release Build. We should decide first if we have a single build-details.json, or one per build. (I suggest discussing that on the issue.)

[encukou]

A single build-details.json is specified in the current PEP. We can always add new ones, but I think the "main" one should stay.

I'll note that Fedora already installs the "regular" optimized build last, precisely to overwrite any common files.

[encukou]

Anyway, this PR fixes an issue you get when installing only the free-threaded build, for example.
The interpreter name that generate-build-details comes up with doesn't match what's in the Makefile.

[FFY00]

This change alone doesn't work, since Free Threading or Debug Build would override build-details.json installed by the regular Release Build.

Only debug builds would, free-threading has its own directory, as of GH-121293.

I opened GH-142269 to only include build-details.json in make install, debug builds installed with make altinstall should no longer include it. I think that makes sense.

[FFY00]

Thanks @befeleme, this looks good. Could you just add a news file, and then we can merge?

[befeleme]

Thank you for adding the news entry!

[FFY00]

No worries! This should have been merged already, but it looks like it was a fluke in the CI. I just restarted it, so hopefully it will merge anytime now 😊

[vstinner]

Tests / All required checks pass (pull_request) Failing after 3s

Ah. We should just update the branch to fix this CI illness.