Add mingw32-w64/wine CI build

[sipa]

No description provided.

[real-or-random]

Nice!

Concept ACK

[real-or-random]

ok it seems there was a reason why -static was there:
https://cirrus-ci.com/task/5119836217933824?logs=test#L185
libtool: warning: undefined symbols not allowed in x86_64-w64-mingw32 shared libraries; building static only (and a few other messages then when linking the benchmarks)

Maybe ./configure --disable-shared does the job then without specifying CFLAGS. In the end it doesn't matter for CI, I was just curious because we could use this to add build docs for mingw.

[real-or-random]

Can you also change
file *tests || true to file *tests* || true ? Otherwise it won't match the ".exe"...

[sipa]

@real-or-random That wasn't the reason actually. I tried this first in the minisketch repository (see bitcoin-core/minisketch#33), and there the issue is that C++ builds to building against shared libgcc by default (something related to being able to catch exceptions across libraries), but I couldn't get that to work with Wine. For C, static libgcc is the default, so this problem doesn't occur. I've just removed it.

[real-or-random]

Ok makes sense. We can take care of more improvements to mingw later then (#923).

ACK mod the file thing.

[sipa]

Can you also change
file *tests || true to file tests || true ? Otherwise it won't match the ".exe"...

Done.

[real-or-random]

ACK e2750b1

[jonasnick]

utACK e2750b1

[jonasnick]

Hm any idea why wine complains so loudly (on cirrus). Is that supposed to be ignored?

it looks like wine32 is missing, you should install it.
as root, please execute "apt-get install wine32"

[sipa]

It's only testing 64-bit binaries, so it doesn't need wine32 I think. We could probably just add it to the dockerfile to silence it.

[real-or-random]

AFAIU wine32 would be required to run 32-bit binaries, which we don't need.

I'm not sure why Wine warns. Maybe because 32bit is still a common thing on Windows and it's an issue that many people run into?

[real-or-random]

@sipa Ok, I played around with the docker container. If I'm not mistaken:

• If you install wine (which pulls in wine64 as dependency), then wine64 <cmd> (or wine64-stable <cmd>) works without the warning
• If you install just wine64, then WINESERVER=/usr/lib/wine/wineserver64 wine64-stable <cmd> works without the warning. (Indeed, without the env variable wineserver can't be found.)

Both are fine but the first is more natural...

By the way, wine xcopy works better as a dummy command. There's no true on windows.

[sipa]

@real-or-random Ok, used your first variant, and also changed true -> xcopy.

[real-or-random]

Ok, great. Now there seems to be one final hiccup:

WARNING: could not read 16 bytes from /dev/urandom; falling back to insecure PRNG

( https://cirrus-ci.com/task/4912068852711424?logs=test#L258 )

I can sometimes reproduce this in the Docker image and then the seed always has some random bytes in front followed by zeros. You can cherry-pick this fix: real-or-random@625b1aa, see https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/fopen-wfopen?view=msvc-160#generic-text-routine-mappings.

[sipa]

@real-or-random Cherry picked.

[real-or-random]

ACK ed5a199

[jonasnick]

utACK ed5a199