[compat] HaikuOS port (#2805)

Still had the issues with libusb, but that should get solved with the other PRs anyways
Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2805
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/dynarmic/src/dynarmic/CMakeLists.txt

@@ -345,7 +345,8 @@ elseif (APPLE)
             backend/exception_handler_macos_mig.c
         )
     endif()
-elseif (UNIX)
+elseif (UNIX AND NOT PLATFORM_HAIKU)
+    # Haiku lacks <ucontext.h>
     if (CMAKE_SYSTEM_NAME STREQUAL "Linux")
         target_link_libraries(dynarmic PRIVATE rt)
     endif()