TLDR: This updates our macOS toolchain to use a newer version of Clang, cctools (including new dependency on libtapi), LD64 and the macOS SDK. I've been testing depends builds (HOST=x86_64-apple-darwin16) inside a Debian Buster Docker container, and running the resultant bitcoind and bitcoin-qt binaries on a macOS 10.14.4 system. The .dmg generated by a make deploy also mounts correctly on the same macOS system. Clang Upgraded from 3.7.1 to 6.0.1 cctools cctools 877.8 -> 921 LD64 253.9 -> 409.12 TAPI 1000.10.8 See tpoechtrager/cctools-port and tpoechtrager/apple-libtapi. macOS SDK Upgraded from building against the macOS 10.11 SDK to the macOS 10.14 SDK.
Backport of core PR16392.
Depends on D5530.