Log Message:
devel/mold: import mold-0.9.3.

mold is a new linker that is optimized for modern multi-core machines.

mold is command-line compatible with the other major linkers, GNU ld, GNU gold
and LLVM lld, yet it is several times faster than them. Its goal is to increase
programmer productivity by speeding up program build time, especially for rapid
edit-build-test-debug cycles.