Yuckily avoid warning.

InstructionSets/ARM/Executor.hpp

@@ -337,7 +337,7 @@ struct Executor {
 			uint32_t value = 0;
 
 			if constexpr (flags.transfer_byte()) {
-				uint8_t target;
+				uint8_t target = 0;	// Value should never be used; this avoids a spurious GCC warning.
 				did_read = bus.template read<uint8_t>(address, target, registers_.mode(), trans);
 				if(did_read) {
 					value = target;

Machines/Acorn/Archimedes/Archimedes.cpp

@@ -548,7 +548,7 @@ class ConcreteMachine:
 		}
 
 		uint32_t advance_pipeline(uint32_t pc) {
-			uint32_t instruction;
+			uint32_t instruction = 0;	// Value should never be used; this avoids a spurious GCC warning.
 			const bool did_read = executor_.bus.read(pc, instruction, executor_.registers().mode(), false);
 			return pipeline_.exchange(
 				did_read ? instruction : Pipeline::SWI,

Processors/68000/Implementation/68000Implementation.hpp

@@ -1869,6 +1869,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
 					SetupDataAccess(0, Operation::SelectWord);
 				MoveToStateSpecific(StoreOperand_l);
 
+				default:	// Convince GCC that nothing here is amiss.
 				case InstructionSet::M68k::DataSize::Word:
 					SetupDataAccess(0, Operation::SelectWord);
 				MoveToStateSpecific(StoreOperand_bw);