Warning fixes:

- Don't use %lu for size_t; they're different on Linux x86.

- has_warned_about_drivers is only used on win32, so only declare it
  there to avoid a unused variable warning.

Source/Core/Core/Src/IPC_HLE/WII_IPC_HLE_Device_hid.cpp

@@ -523,7 +523,9 @@ libusb_device_handle * CWII_IPC_HLE_Device_hid::GetDeviceByDevNum(u32 devNum)
 	if (cnt < 0)
 		return NULL;
 
+#ifdef _WIN32
 	static bool has_warned_about_drivers = false;
+#endif
 
 	for (i = 0; i < cnt; i++) {
 		libusb_device *device = list[i];

Source/Core/DolphinWX/Src/ARCodeAddEdit.cpp

@@ -108,9 +108,9 @@ void CARCodeAddEdit::SaveCheatData(wxCommandEvent& WXUNUSED (event))
 		}
 
 		// If the above-mentioned conditions weren't met, then something went wrong.
-		if (!PanicYesNoT("Unable to parse line %lu of the entered AR code as a valid "
+		if (!PanicYesNoT("Unable to parse line %u of the entered AR code as a valid "
 						"encrypted or decrypted code.  Make sure you typed it correctly.\n"
-						"Would you like to ignore this line and continue parsing?",  i + 1))
+						"Would you like to ignore this line and continue parsing?", (unsigned) (i + 1)))
 		{
 			return;
 		}

Source/Core/DolphinWX/Src/ISOProperties.cpp

@@ -887,7 +887,7 @@ void CISOProperties::OnExtractDataFromHeader(wxCommandEvent& event)
 		}
 		else
 		{
-			PanicAlertT("Partition doesn't exist: %lu", partitionNum);
+			PanicAlertT("Partition doesn't exist: %u", (unsigned) partitionNum);
 			return;
 		}
 	}