Fix build

Author: TiKevin83

src/BizHawk.Common/EndiannessUtils.cs

@@ -31,7 +31,7 @@ public static void MutatingByteSwap32(Span<byte> a)
 			fixed (byte* p = &a[0]) for (var i = 0; i < l; i += 4)
 			{
 					(p[i + 3], p[i]) = (p[i], p[i + 3]);
-					b = p[i + 1];
+					var b = p[i + 1];
 				p[i + 1] = p[i + 2];
 				p[i + 2] = b;
 			}

src/BizHawk.Emulation.Cores/CPUs/Z80A/Operations.cs

@@ -651,7 +651,7 @@ public void ADDS_Func(ushort dest_l, ushort dest_h, ushort src_l, ushort src_h)
 		public void EXCH_16_Func(ushort dest_l, ushort dest_h, ushort src_l, ushort src_h)
 		{
 			(Regs[src_l], Regs[dest_l]) = (Regs[dest_l], Regs[src_l]);
-			temp = Regs[dest_h];
+			var temp = Regs[dest_h];
 			Regs[dest_h] = Regs[src_h];
 			Regs[src_h] = temp;
 		}

src/BizHawk.Tests/Emulation.Common/Base Implementations/MemoryCallbackSystemTests.cs

@@ -208,7 +208,7 @@ public void TestAddingCallbackWithinCallback()
 			MemoryCallback callback3 = new(ScopeA, MemoryCallbackType.Read, "Callback 3", _testCallbacks.Callback3, null, null);
 
 			var callback1invoked = false;
-			void callback(uint _, uint _, uint _)
+			void callback(uint _1, uint _2, uint _3)
 			{
 				callback1invoked = true;
 				_memoryCallbackSystem.Add(callback2);
@@ -233,7 +233,7 @@ public void TestRemovingCallbackWithinCallback()
 			MemoryCallback callback1 = new(ScopeA, MemoryCallbackType.Read, "Callback 1", _testCallbacks.Callback1, null, null);
 
 			var callback2invoked = false;
-			void callback(uint _, uint _, uint _)
+			void callback(uint _1, uint _2, uint _3)
 			{
 				callback2invoked = true;
 				_memoryCallbackSystem.Remove(callback1.Callback);
@@ -264,7 +264,7 @@ public void TestRemovingSelfWithinCallback()
 
 			MemoryCallback? callback2 = null;
 			var callback2invoked = false;
-			void callback(uint _, uint _, uint _)
+			void callback(uint _1, uint _2, uint _3)
 			{
 				callback2invoked = true;
 				_memoryCallbackSystem.Remove(callback2!.Callback);