closes #829

--print-multiarch reporting an incorrect triple was a bug in LLVM that
was fixed. With the project now using LLVM 21+ (#916) the patches to
remove this check during configuration are no necessary.

closes #865

A version of `patch-test-embed-prevent-segfault.patch` was merged
upstream in python/cpython#128474. It is not
needed in CPython 3.14+

Rename the script used to start a build from `build-uv.py` to
`build.py`.
On all platforms builds can be done using:
```
uv run ./build.py ...
```
Additionally on Linux and macOS `./build.py ...` can be used.

closes #430

Correctly handle lines missing a filename (which have a space between
fields immediately followed by a newline; scanf will skip over both of
those as whitespace and try to parse the next line).

Also use __builtin_return_address to provide some robustness against
running into issues with the PLT.

Backport the changes to library_to_dict() (the function we're patching
in 3.14) in Modules/getpath.c with the help of

    git checkout -p v3.14.0 -- Modules/getpath.c