Restore libbitcoinconsensus

[luke-jr]

Actual code unchanged, but build significantly reworked for CMake

[bigshiny90]

Testing Report
Tested on: Ubuntu 22.04, GCC 11.4.0

• ✅ Builds successfully with -DBUILD_BITCOINCONSENSUS_LIB=ON
• ✅ Default build unchanged with -DBUILD_BITCOINCONSENSUS_LIB=OFF (default)
• ✅ pkg-config integration functional
• ✅ All unit tests pass
• ✅ All functional tests pass
• ✅ CMake changes look appropriate

let me know if there is anything else i can help with on this review

[chrisguida]

For some reason the progress meter only goes up to 1% when I build with cmake -B build -DBUILD_BITCOINCONSENSUS_LIB=ON

But it appears to build properly when I use just cmake -B build instead.

[chrisguida]

Maybe my build dir is just broken? What's the cmake equivalent of make clean?

[bigshiny90]

Maybe my build dir is just broken? What's the cmake equivalent of make clean?

rm -rf build

😂. (Or whatever your build directory is…)

[chrisguida]

@bigshiny90 yep, that fixed it!

This PR works great then.

ACK

[bigshiny90]

@bigshiny90 yep, that fixed it!

yeah, i think there IS an arg with cmake to do it, just not as easy as the rm -rf..