ci: add OpenBSD Clang cross job #35397

This adds a Linux cross job for OpenBSD; similar to #34491 (FreeBSD). Depends Qt builds, but CMake can't seem to find it, so I have dropped Qt for now. bitcoin-chainstate and test_kernel currently fail to link when I run this locally (aarch64):

[ 69%] Linking CXX executable ../../../bin/test_kernel
ld.lld: error: non-exported symbol '__cxa_atexit' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(atexit.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol '__stack_smash_handler' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(stack_protector.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol '__assert2' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(assert.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'free' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(malloc.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'memset' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(memset.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'memcpy' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(memcpy.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'memmove' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(memmove.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'strlen' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(strlen.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'malloc' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(malloc.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'realloc' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(malloc.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'memcmp' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(memcmp.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'abort' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(abort.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'vsnprintf' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(vsnprintf.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'fseek' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(fseek.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'fclose' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(fclose.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'setbuf' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(setbuf.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'fwrite' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(fwrite.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol '__stdout' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(findfp.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'fflush' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(fflush.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: non-exported symbol 'fread' in '/ci_container_base/depends/SDKs/openbsd-x86_64-unknown-openbsd-7.9/usr/lib/libc.a(fread.o)' is referenced by DSO '../../../lib/libbitcoinkernel.so'
ld.lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors)
clang++: error: linker command failed with exit code 1 (use -v to see invocation)

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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35397.

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Conflicts

No conflicts as of last run.

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bitcoin-chainstate and test_kernel currently fail to link

cc @sedited

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🚧 At least one of the CI tasks failed. _{Task OpenBSD Cross: https://github.com/bitcoin/bitcoin/actions/runs/26520966708/job/78111604124} _{LLM reason (✨ experimental): ld.lld failed to link bitcoin-chainstate due to “non-exported symbol” errors from the OpenBSD SDK’s libc.a (e.g., __cxa_atexit, malloc, memcpy, strlen).}

<details><summary>Hints</summary>

Try to run the tests locally, according to the documentation. However, a CI failure may still happen due to a number of reasons, for example:

• Possibly due to a silent merge conflict (the changes in this pull request being incompatible with the current code in the target branch). If so, make sure to rebase on the latest commit of the target branch.

• A sanitizer issue, which can only be found by compiling with the sanitizer and running the affected test.

• An intermittent issue.

Leave a comment here, if you need help tracking down a confusing failure.

</details>

Concept ACK

I guess a similar treatment could also be done for freebsd.

I guess a similar treatment could also be done for freebsd.

Do you mean NetBSD? We added a Clang cross FreeBSD job in #34491.

Depends Qt builds, but CMake can't seem to find it, so I have dropped Qt for now.

cc @hebasto, you might want to have a look here.

I guess a similar treatment could also be done for freebsd.

Do you mean NetBSD?

Yeah, given that apparently all three of them can run into unrelated/orthogonal(?) build issues, it could make sense to check all of them

Do you mean NetBSD? We added a Clang cross FreeBSD job in #34491.

Yes, not sure why I confused them.

Put up something for NetBSD here: #35412.