Junio C Hamano [off-list ref] writes:

But the patch seems to indicate somewhat different story.  The code
before this patch started with a single macOS (darwin) one, but
because it is mostly applicable to other UNIX variants as well, the
patch renames the existing macOS one for unix and makes a small
adjustment (namely, asserts that r->worktree is not NULL).

Good point. Restructured: FSMONITOR_OS_SETTINGS is now set to "unix"
for both macOS and Linux (and "win32" for Windows). The build files
use $(FSMONITOR_OS_SETTINGS) for fsm-ipc and fsm-settings, and
$(FSMONITOR_DAEMON_BACKEND) for the platform-specific files (listen,
health, path-utils). No more if/else blocks.

Also rewrote both commit messages to describe what's actually
happening (renaming darwin to unix) rather than "merging two
implementations".

Thanks,
Paul