Zig fails to build from source on latest Debian/Ubuntu against system LLVM package

[andrewrk]

[ 11%] Building CXX object CMakeFiles/zig_cpp.dir/src/zig_llvm.cpp.o
/home/vsts/work/1/s/src/zig_llvm.cpp:1037:59: error: ‘KFreeBSD’ is not a member of ‘llvm::Triple’
 static_assert((Triple::OSType)ZigLLVM_KFreeBSD == Triple::KFreeBSD, "");
                                                           ^~~~~~~~

See https://dev.azure.com/ziglang/zig/_build/results?buildId=966

See #2001

This appears to be an accident in the packaging process and I have filed a Debian bug.

As a workaround, one can use http://apt.llvm.org/.

[andrewrk]

This is a bug in Debian, but it's unclear that they have any interest in fixing it, and we've worked around it in the Zig repository. So I'm closing the tracking issue.