Disable runtime floating point exceptions

Clang 15+ / GCC 13+ leave us no choice but to disable floating point exceptions.
Their auto-vectorization optimizations load invalid values and will cause FPEs even when fp-strict is enabled.

src/Pi.cpp

@@ -871,6 +871,12 @@ static void OnPlayerDockOrUndock();
 void GameLoop::Start()
 {
 	PROFILE_SCOPED()
+
+	// NOTE: this is here because Clang 15+ and GCC 13+ ignore fp-model when
+	// generating vectorized/optimized code and will happily perform exception-
+	// raising operations on the contents of uninitialized or aliased memory
+	OS::DisableFPE();
+
 	// this is a bit brittle. skank may be forgotten and survive between
 	// games
 	Pi::input->InitGame();

src/ship/PlayerShipController.cpp

@@ -495,9 +495,7 @@ void PlayerShipController::StaticUpdate(const float timeStep)
 {
 	// call autopilot AI, if active
 	if (m_ship->AIIsActive()) {
-		OS::EnableFPE();
 		m_ship->AITimeStep(timeStep);
-		OS::DisableFPE();
 		// the speed limiter should not work when the autopilot is working
 		if (IsSpeedLimiterActive()) SetSpeedLimiterActive(false);
 		return;

src/ship/ShipController.cpp

@@ -7,7 +7,5 @@
 
 void ShipController::StaticUpdate(float timeStep)
 {
-	OS::EnableFPE();
 	m_ship->AITimeStep(timeStep);
-	OS::DisableFPE();
 }