fixes from pypy

[mattip]

• add proper function declarations
• skip a few tests that fail on PyPy

I found these when updating PyPy to work with latest HEAD here. It might be nice to release 0.9.1 so there is a tag to use for the cython benchmarks at https://github.com/DuToitSpies/msc_cython_benchmarks

[mattip]

The image changed to ubuntu24.04 and now python3.10 installation is different?

sudo apt-get install -y --no-install-recommends python3.10-dev python3.10-venv python3-distutils python3.10-dbg
  Reading package lists...
  Building dependency tree...
  Reading state information...
  Package python3-distutils is not available, but is referred to by another package.
  This may mean that the package is missing, has been obsoleted, or
  is only available from another source

[mattip]

And on windows, the build also fails

D:\a\hpy\hpy\hpy\universal\src\autogen_ctx_def.h(181): \
    error C2220: the following warning is treated as an error
  D:\a\hpy\hpy\hpy\universal\src\autogen_ctx_def.h(181): \
                     warning C4113: 'void (__cdecl *)(HPyContext *,HPyFunc_Signature,void *(__cdecl *)(),void *)' 
    differs in parameter lists from 'void (__cdecl *)(HPyContext *,HPyFunc_Signature,HPyCFunction,void *)'
  error: command 'C:\\Program Files\\Microsoft Visual Studio\\2022\\Enterprise\\VC\\Tools\\MSVC\\14.42.34433\\bin\\HostX86\\x64\\cl.exe' failed with exit code 2

[hodgestar]

Looks good to me.