cmake: Remove NetBSD-specific workaround from `add_boost_if_needed` #35165

The patched package boost-1.90.0 is available as of the pkgsrc-2026Q1 release.

<!--e57a25ab6845829454e8d69fc972939a-->

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

<!--021abf342d371248e50ceaed478a90ca-->

Reviews

See the guideline for information on the review process.

If your review is incorrectly listed, please copy-paste <code>&lt;!--meta-tag:bot-skip--&gt;</code> into the comment that the bot should ignore.

<!--5faf32d7da4f0f540f40219e4f7537a3-->

Tested ACK https://github.com/bitcoin/bitcoin/pull/35165/commits/e2ef54b8ba8de7ce1d7b1b04c3e28b08c3fa3816

This branch works on a fresh install of NetBSD 10.1.

One small caveat is that users may have a /usr/pkg/etc/pkgin/repositories.conf pinned to an earlier quarterly, e.g.

https://ftp.netbsd.org/pub/pkgsrc/packages/NetBSD/x86_64/10.0_2025Q4/All

so maybe a note in doc/build-netbsd.md or in the release notes about the minimum supported netbsd version, but I'm also OK as-is as I suspect that not many users do this but I am unfamiliar.

One small caveat is that users may have a /usr/pkg/etc/pkgin/repositories.conf pinned to an earlier quarterly, e.g.

https://ftp.netbsd.org/pub/pkgsrc/packages/NetBSD/x86_64/10.0_2025Q4/All

so maybe a note in doc/build-netbsd.md or in the release notes about the minimum supported netbsd version, but I'm also OK as-is as I suspect that not many users do this but I am unfamiliar.

Our documentation implicitly relies on OS default settings.

The build notes for *BSD systems are maintained to be correct for the release explicitly mentioned at their top. However, we do our best to ensure that Bitcoin Core builds and runs on all supported releases, which is currently true except for OpenBSD.

If you believe that our *BSD build notes could be improved, a PR is always welcome :)

Guix Build (arm64):

39b30ecb61176599321cd5fe3b157c42d36bb97d05401028be1c7df7561abd36  guix-build-e2ef54b8ba8d/output/aarch64-linux-gnu/SHA256SUMS.part
cc585ae57a8ea776acbfe573f72249dd2c9d4e40c132bcf4824ae5f0109798df  guix-build-e2ef54b8ba8d/output/aarch64-linux-gnu/bitcoin-e2ef54b8ba8d-aarch64-linux-gnu-debug.tar.gz
60f3ed48c15a0bc19fa31f4c21e2d36ed33dbd15a2402af2b9652cdf4e42d7b8  guix-build-e2ef54b8ba8d/output/aarch64-linux-gnu/bitcoin-e2ef54b8ba8d-aarch64-linux-gnu.tar.gz
6d7f7f6a70d14e2d5d9479be772bfddacafd38d2bcda45f370ef06f205b68d19  guix-build-e2ef54b8ba8d/output/arm-linux-gnueabihf/SHA256SUMS.part
aba31a380d7d77d0af221181662dfa0c779d02d860365a75349b8201acbcf33c  guix-build-e2ef54b8ba8d/output/arm-linux-gnueabihf/bitcoin-e2ef54b8ba8d-arm-linux-gnueabihf-debug.tar.gz
51524fc3d80e0ba7707348a69e8c74e1a76e7e94852c6f47bfb568dbcfa58419  guix-build-e2ef54b8ba8d/output/arm-linux-gnueabihf/bitcoin-e2ef54b8ba8d-arm-linux-gnueabihf.tar.gz
d4e501c506d17c1a093ea9ed3dfb3c8d1e9607f9d44c23cb50a8f03d4711322c  guix-build-e2ef54b8ba8d/output/arm64-apple-darwin/SHA256SUMS.part
492303b717543e18915e3611d403a416517191d9a2c79a9e0cf45738c49804ed  guix-build-e2ef54b8ba8d/output/arm64-apple-darwin/bitcoin-e2ef54b8ba8d-arm64-apple-darwin-codesigning.tar.gz
18b05d48612a555827d4544635c7d7607df032f2840f066f3c376fd0549e7fe8  guix-build-e2ef54b8ba8d/output/arm64-apple-darwin/bitcoin-e2ef54b8ba8d-arm64-apple-darwin-unsigned.tar.gz
97069a0bab56bfd02def750213fecdf14702cc7b07833b16b56ce29f16f314a9  guix-build-e2ef54b8ba8d/output/arm64-apple-darwin/bitcoin-e2ef54b8ba8d-arm64-apple-darwin-unsigned.zip
b209b60a0e5cbac63a800d37302d3387216d7463c3df7c98e5e4c09773bf26d2  guix-build-e2ef54b8ba8d/output/dist-archive/bitcoin-e2ef54b8ba8d.tar.gz
12ed8844f03505bfe268a29861f3f034be62ef4acd495029a65b46e012542775  guix-build-e2ef54b8ba8d/output/powerpc64-linux-gnu/SHA256SUMS.part
09c152ab857292600b0143381249a26615d847669f7224a55bb88788513134bb  guix-build-e2ef54b8ba8d/output/powerpc64-linux-gnu/bitcoin-e2ef54b8ba8d-powerpc64-linux-gnu-debug.tar.gz
6efc873998528202f94cbd47918e9049456229ab9eb1763809fdf1789bd39b37  guix-build-e2ef54b8ba8d/output/powerpc64-linux-gnu/bitcoin-e2ef54b8ba8d-powerpc64-linux-gnu.tar.gz
c833be5b498a009afa96b1a7ee24aa43a7f4e5ce443a8a8759742b4808af0a79  guix-build-e2ef54b8ba8d/output/riscv64-linux-gnu/SHA256SUMS.part
d0eec379b0a992f5e6f1d715d1761619c45d730f3b2f152da03fe56836108a24  guix-build-e2ef54b8ba8d/output/riscv64-linux-gnu/bitcoin-e2ef54b8ba8d-riscv64-linux-gnu-debug.tar.gz
6a00e313b11ed31006f3c94ddd28905ce4273fc270b29477cbc27a4ba395f107  guix-build-e2ef54b8ba8d/output/riscv64-linux-gnu/bitcoin-e2ef54b8ba8d-riscv64-linux-gnu.tar.gz
695e8a8d43c847f3f86798704b494c1dba13a082d0dcdc1348259dd4b42f3a02  guix-build-e2ef54b8ba8d/output/x86_64-apple-darwin/SHA256SUMS.part
603e732211586221120f702d43e36802d51dd4ff1c8d0be1815a79be170daada  guix-build-e2ef54b8ba8d/output/x86_64-apple-darwin/bitcoin-e2ef54b8ba8d-x86_64-apple-darwin-codesigning.tar.gz
d95708a1a5b47f5c2650ce6154bd4612735879699c258253bf1bf7249780d9b6  guix-build-e2ef54b8ba8d/output/x86_64-apple-darwin/bitcoin-e2ef54b8ba8d-x86_64-apple-darwin-unsigned.tar.gz
bb3337d8afcfd388bafe8bd66acb20ee747dbc06b5b230435ac7359a00cabe68  guix-build-e2ef54b8ba8d/output/x86_64-apple-darwin/bitcoin-e2ef54b8ba8d-x86_64-apple-darwin-unsigned.zip
a3c965959e5d0e38e6a272fb24ee581f13d3fdf46bd4165f21da8eb223b41b80  guix-build-e2ef54b8ba8d/output/x86_64-linux-gnu/SHA256SUMS.part
26c5f93206facc5b6d9503f17044e799cb5b684f731493d5bc3e33434fac0df1  guix-build-e2ef54b8ba8d/output/x86_64-linux-gnu/bitcoin-e2ef54b8ba8d-x86_64-linux-gnu-debug.tar.gz
9a3736528636e92a25f962c85f4a6e7cc1e3a901312c769c33c1f69ae06cbb0d  guix-build-e2ef54b8ba8d/output/x86_64-linux-gnu/bitcoin-e2ef54b8ba8d-x86_64-linux-gnu.tar.gz
711a32777158d63d4111e3bc23f27747b771dece0a1c2491a7ba4f503c6b191d  guix-build-e2ef54b8ba8d/output/x86_64-w64-mingw32/SHA256SUMS.part
94229a16358c5c2a661a91cfd2072bd8af63312f946c583b9de2e5d95118febf  guix-build-e2ef54b8ba8d/output/x86_64-w64-mingw32/bitcoin-e2ef54b8ba8d-win64-codesigning.tar.gz
0788b988b7803e8752d9e3aef704415f464c5229339328ac3f78395af6703be5  guix-build-e2ef54b8ba8d/output/x86_64-w64-mingw32/bitcoin-e2ef54b8ba8d-win64-debug.zip
421776a2a715295085a7ed15cd94fa294666157dd8aa9b1a217abf643a996ff8  guix-build-e2ef54b8ba8d/output/x86_64-w64-mingw32/bitcoin-e2ef54b8ba8d-win64-setup-unsigned.exe
3758740bb780ce7d11265ebf1e0d024a77cb42786310ad2e0cfb7b2c1fca46df  guix-build-e2ef54b8ba8d/output/x86_64-w64-mingw32/bitcoin-e2ef54b8ba8d-win64-unsigned.zip

ACK e2ef54b8ba8de7ce1d7b1b04c3e28b08c3fa3816