mkvtoolnix-legacy @81.0: fatal error: no template named '_mp_size'

[sambthompson (Sam Thompson)]

mkvtoolnix-legacy @ 81.0_1 fails to build on MacOS Mojave 10.14.6:

​https://build.macports.org/builders/ports-10.14_x86_64-builder/builds/215343/steps/install-port/logs/stdio

In file included from src/common/common.h:47:
/opt/local/libexec/boost/1.81/include/boost/multiprecision/gmp.hpp:382:11: fatal error: no template named '_mp_size'; did you mean 'mp11::mp_size'?

Appears to relate to this clang parsing bug: ​https://bugs.llvm.org/show_bug.cgi?id=43266 from 2019, which is present in clang 11, supplied with Xcode 11.3.1. It was reported against clang 8.0 but it's not clear from the clang report which other versions are affected; the Xcode 11.3.1 clang is from about the same time in 2019.

Anyway, overriding compiler with configure.compiler=macports-clang-17 allows successful build. In the portfile, compliler blacklist already includes clang < 1001. Maybe needs to be bumped to 1101, but I haven't tested all other clang versions.