Bug-fix: if UART virtualization was disabled, input_thread would hang after the

first input character as it was attempting to use an uninitialized critical
section (mutex) while asserting the UART interrupt. As long as the UART
virtualization is enabled, this problem doesn't happen, even if don't actually
*use* the UART virtualization.

src/sbbs3/sbbsexec.c

@@ -232,10 +232,13 @@ void _cdecl input_thread(void* arg)
 			continue;
 		}
 		RingBufWrite(&rdbuf,buf,count);
-		/* Set the "Data ready" bit in the LSR */
-		uart_lsr_reg |= UART_LSR_DATA_READY;
 
-		assert_interrupt(UART_IER_RX_DATA); /* assert rx data interrupt */
+		if(virtualize_uart) {
+			/* Set the "Data ready" bit in the LSR */
+			uart_lsr_reg |= UART_LSR_DATA_READY;
+
+			assert_interrupt(UART_IER_RX_DATA); /* assert rx data interrupt */
+		}
 	}
 }