[cmake, compat] fix solaris boost build once and for all (#364)

Signed-off-by: lizzie <lizzie@eden-emu.dev>
Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/364
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

CMakeLists.txt

@@ -406,8 +406,10 @@ if (YUZU_USE_CPM)
 
         if (NOT MSVC)
             # boost sucks
-            if (NOT PLATFORM_LINUX AND NOT ANDROID)
-                target_compile_definitions(boost_container INTERFACE BOOST_HAS_PTHREADS)
+            # Solaris (and probably other NIXes) need explicit pthread definition
+            if (PLATFORM_SUN)
+                set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthreads")
+                set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthreads")
             endif()
 
             target_compile_options(boost_heap INTERFACE -Wno-shadow)