Include the MINGW-package downstream patch

[swilmet]

Include the MINGW-package downstream patch.

See 001_fix_relocation.patch

[swilmet]

It is a small patch that fixes the issue that dictionaries are not found.

[rrthomas]

I translated the patch to Vala and added it on a branch (see linked branch win32-relocatable).

However, I would like to know more about why the patch is needed, and what the problem is in gnulib. Looking at gnulib's relocatable.c, it has a special DllMain function specifically for Win32, so it looks like relocatability should work; perhaps I'm not using it right?

Also, I would rather make any patch to gnulib (since it does not rely on formal releases, I don't have to wait for that before then using a new version in Enchant).

Finally, adding Windows-specific code to Enchant would mean that users would have to compile the Vala rather than the C sources, and hence would need to install a Vala compiler.

[rrthomas]

Also, I don't seem to have the patch quite right yet, as it makes the Windows tests segfault: https://github.com/rrthomas/enchant/actions/runs/12637182516/job/35210842868#step:7:210

[swilmet]

I'm not the author of the patch, so I don't know the details. I would need to investigate how it works and why it is needed. (A bit out of scope for me right now)