Patch to support extended baud rates

[albertogonb]

I ask you to add the following patch to support 230400, 500000 and 1000000 Baud.
I have successfully tested these speeds on Fedora 31 and Raspbian 10.
The patch is for version 0.4.0.

--- src/tty.c.orig	2020-07-13 18:48:41.397491648 +0200
+++ src/tty.c	2020-07-16 20:06:23.600114131 +0200
@@ -306,6 +306,21 @@
     tspeed = B115200;
     break;
 #endif
+#if defined(B230400)
+  case 230400:
+    tspeed = B230400;
+    break;
+#endif
+#if defined(B500000)
+  case 500000:
+    tspeed = B500000;
+    break;
+#endif
+#if defined(B1000000)
+  case 1000000:
+    tspeed = B1000000;
+    break;
+#endif
   default:
     tspeed = DEFAULT_BSPEED;
     break;