[cmake, compat] fix solaris boost build once and for all

Signed-off-by: lizzie <lizzie@eden-emu.dev>

CMakeLists.txt

@@ -406,8 +406,12 @@ if (YUZU_USE_CPM)
 
         if (NOT MSVC)
             # boost sucks
-            if (NOT PLATFORM_LINUX AND NOT ANDROID)
+            # Specific workaround for a bug of Solaris builds - even through -pthread is defined
+            # Solaris has some nasty /usr/include hierachy that makes boost config freak out
+            if (PLATFORM_SUN)
                 target_compile_definitions(boost_container INTERFACE BOOST_HAS_PTHREADS)
+                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)