Various small warning fixes

-Indentation warnings
-prevent shift overflow
-This was declared extern in all contexts. Remove this for initialization
-Fix main return types. OH CANADA!
-Silence extraneos 'unused expression' warning
-Force use return value (warning)
-Remove tautological compare copy-pasta (char always < 256)

Utilities/Thread.cpp

@@ -1394,7 +1394,10 @@ bool handle_access_violation(u32 addr, bool is_writing, x64_context* context)
 			}
 
 			// Reschedule
-			cpu->test_stopped();
+			if (cpu->test_stopped())
+			{
+				//
+			}
 
 			if (Emu.IsStopped())
 			{
@@ -1692,7 +1695,7 @@ const bool s_exception_handler_set = []() -> bool
 #endif
 
 // TODO
-extern atomic_t<u32> g_thread_count(0);
+atomic_t<u32> g_thread_count(0);
 
 thread_local DECLARE(thread_ctrl::g_tls_this_thread) = nullptr;