PR summary

Fixes #31964.

Fixes invalid Meson variable names generated by the f2py Meson backend for -l libraries whose names are valid linker library names but are not valid Meson identifiers.

#26634 handled dotted library names by replacing . with _, but other inputs can still break or become ambiguous when the raw library name is used as the Meson variable name. For example, a library such as scalapack-openmpi can lead to an invalid assignment target in the generated meson.build.

This PR separates the internal Meson variable name from the user-provided linker library name. The generated dependency variable now uses a private indexed identifier, while the linker argument still preserves the original value, e.g. -lscalapack-openmpi remains -lscalapack-openmpi.

The regression test parses the generated meson.build and asserts that the generated dependency declarations preserve the original -l<name> linker arguments, while the unsafe original library names are not used directly as Meson assignment targets. It covers dotted, hyphenated, realistic hyphenated, underscore/collision, and digit-leading library names:

• foo.bar
• scalapack-openmpi
• foo-bar
• foo_bar
• 1foo

Validation performed locally:

• git diff --check
• spin lint
• A direct MesonTemplate parser check using mesonbuild.mparser.Parser(...).parse(), which completed with parse-ok and verified that generated dependency declarations preserve the original -l... arguments.

I also attempted the focused pytest command below, but this unbuilt local source checkout stops during NumPy test configuration before selected tests run because the generated numpy.version module is unavailable:

D:\ZXY\Dev\Miniforge3\envs\prw-numpy-py312\python.exe -m pytest numpy/f2py/tests/test_regression.py -q -k "meson_library_names or gh26623"

First time committer introduction

N/A.

AI Disclosure

Codex was used to investigate the failing f2py/Meson code path, draft the small code and regression-test change, run focused local validation, and draft this PR description. The diff and submission were reviewed by a human before opening the PR.