Add native FreeBSD building functionality (#35)

This commit enables native building on FreeBSD through Cmake + ninja.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/35
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: SDK-Chan <sdkchan@eden-emu.dev>
Co-committed-by: SDK-Chan <sdkchan@eden-emu.dev>

src/core/CMakeLists.txt

@@ -1150,7 +1150,7 @@ add_library(core STATIC
     tools/renderdoc.h
 )
 
-if (UNIX AND NOT APPLE AND NOT ANDROID)
+if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
     # find_package(libiw REQUIRED)
     target_link_libraries(core PRIVATE iw)
 endif()