Add ncurses tinfo static library to link path

[vanzod]

If statically linking against the ncurses library built with separate terminfo library (i.e. configured with --with-termlib), Python building step fails to find required symbols unless the terminfo library is added to the linking paths.

[boegel]

@vanzod I'd prefer avoiding to copy-paste as much as possible, how about this:

ncurses_static_libs = os.path.join(ncurses, ncurses_libdir, 'libncurses.a')
tinfo_static_lib = os.path.join(ncurses, ncurses_libdir, 'libtinfo.a')
# if libtinfo.a exists, we also need to link it in to resolve all ncurses symbols
if os.path.exists(tinfo_static_lib):
    ncurses_static_libs += ' ' + tinfo_static_lib
readline = "readline readline.c %s %s" % (readline_static_lib, ncurses_static_libs)

[vanzod]

@boegel Do not merge this PR yet since there are still issues with the terminfo library.

[vanzod]

Closing as issue has been solved. See easybuilders/easybuild-easyconfigs#4049

[boegel]

@pforai Just mentioned to me that he was hitting the problem being fixed here after enabling the use of --add-dummy-to-minimal-toolchains with --minimal-toolchains.

Due to this, ncurses-6.0.eb is being picked up, where libtinfo.a is split off, as opposed to in the other ncurses easyconfigs.

So maybe this change should be applied after all?

@vanzod Did you run into other problems with the Python you obtained with this patch applied? Which other issues with the terminfo library made you put this on hold?

[vanzod]

No, this fix does not solve the problem either since I still got an error because the libtinfo.a is not position independent despite -fPIC. See my Jan 23 comment in easybuilders/easybuild-easyconfigs#4049.

edit: see easybuilders/easybuild-easyconfigs#4049 (comment)

[ocaisa]

Hopefully this is solved with easybuilders/easybuild-easyconfigs#5067