Do not build on the BSDs: hwinfo has no backend for them

[jcelerier]

This add-on is the single thing that stops ossia/score from compiling on FreeBSD. With it out of the way, the rest of the tree builds and links cleanly there.

What is broken

hwinfo picks a backend in include/hwinfo/platform.h:

#if defined(unix) || defined(__unix) || defined(__unix__)
#define HWINFO_UNIX
#endif

The backend it calls "unix" is really the Linux one — every file under src/linux/ reads /proc and /sys, and two of them use interfaces that only exist on Linux:

file	uses	FreeBSD equivalent
src/linux/network.cpp	<netpacket/packet.h>, AF_PACKET	<net/if_dl.h>, AF_LINK
src/linux/ram.cpp	sysconf(_SC_AVPHYS_PAGES)	sysctl vm.stats.vm.v_free_count

FreeBSD defines __unix__, so it selects that backend and those two files fail:

src/linux/network.cpp:8:10: fatal error: 'netpacket/packet.h' file not found
src/linux/ram.cpp:29:37: error: use of undeclared identifier '_SC_AVPHYS_PAGES'

Why skip rather than shim

I compiled every hwinfo source on FreeBSD 15.0 one by one — those two are the only failures, so a pair of shims in hwinfo.cmake would make it build. But it would not make it work: the files that do compile read /proc/cpuinfo, /proc/stat, /proc/meminfo, /sys/class/net, /sys/class/drm, /sys/block, /sys/class/power_supply, /sys/devices/virtual/dmi. None of those are there on a FreeBSD box, so the add-on would ship a device tree that is empty end to end.

The fix worth having is a real BSD backend upstream in lfreist/hwinfo — getifaddrs + AF_LINK for the network side, sysctl(3) (hw.physmem, vm.stats.vm.*, hw.model, kern.disks, kern.osrelease) for the rest. That is a backend, not a shim, and it does not belong in this repository. Until it exists, do not build the add-on there.

The change

One guard in CMakeLists.txt, next to the existing EMSCRIPTEN one:

if(CMAKE_SYSTEM_NAME MATCHES "BSD|DragonFly")
  message(STATUS "score-addon-sysinfo: hwinfo has no ${CMAKE_SYSTEM_NAME} backend, skipping")
  return()
endif()

Nothing on Linux, macOS or Windows is touched — CMAKE_SYSTEM_NAME is Linux / Darwin / Windows there.

How it was verified

In a FreeBSD 15.0 VM built from the same vmactions/freebsd-builder image the CI uses, with the 265 packages .github/workflows/bsd.yml installs:

• every hwinfo translation unit compiled individually with c++ -std=c++20 → exactly the two errors above, nothing else;
• a full ci/freebsd.build.sh of score with this add-on present and this patch applied → configures (score-addon-sysinfo: hwinfo has no FreeBSD backend, skipping), compiles and installs.

Note that ossia/score's FreeBSD job never noticed any of this: ci/freebsd.build.sh exited 127 on its shebang and the workflow swallowed the status. That half is fixed in ossia/score#2213; this PR should land first, otherwise that one turns the job red.

[jcelerier]

Verified in a FreeBSD 15.0 VM (same vmactions/freebsd-builder image ossia/score's job uses, same packages), building the add-on inside a real score tree.

Before, ninja score_addon_sysinfo_hwinfo gets 42 of 44 objects and then:

[43/44] Building CXX object .../hwinfo/src/linux/network.cpp.o
FAILED: [code=1]
  .../src/linux/network.cpp:8:10: fatal error: 'netpacket/packet.h' file not found
[44/44] Building CXX object .../hwinfo/src/linux/ram.cpp.o
FAILED: [code=1]
  .../src/linux/ram.cpp:29:37: error: use of undeclared identifier '_SC_AVPHYS_PAGES'
ninja: build stopped: subcommand failed.

Those 42 are the ones that do compile — the whole apple and windows backends compile to nothing there, and the rest of src/linux/ builds fine but only reads procfs and sysfs paths FreeBSD does not have. Hence skipping rather than shimming.

After:

 -- score: configuring score-addon-sysinfo
-- score-addon-sysinfo: hwinfo has no FreeBSD backend, skipping

and ci/freebsd.build.sh then compiles, links and installs the whole of score, ossia-score binary included.

The Ubuntu / Windows / JIT checks on this PR are red on main too (see the runs of 2026-08-08); this patch adds a CMAKE_SYSTEM_NAME MATCHES "BSD|DragonFly" guard and touches nothing else, so it cannot be the cause.