stty doesn't support all baud rates available in current Linux kernels.

When trying to set a high baud rate using stty, it says "invalid
argument". When the high rate is already configured, "stty -a"
returns 0 instead of the true baud rate.

(struct speeds): Add support for all baud rates defined
in linux-2.4.19.

src/stty.c

@@ -1794,6 +1794,39 @@ struct speed_map speeds[] =
 #endif
 #ifdef B460800
   {"460800", B460800, 460800},
+#endif
+#ifdef B500000
+  {"500000", B500000, 500000},
+#endif
+#ifdef B576000
+  {"576000", B576000, 576000},
+#endif
+#ifdef B921600
+  {"921600", B921600, 921600},
+#endif
+#ifdef B1000000
+  {"1000000", B1000000, 1000000},
+#endif
+#ifdef B1152000
+  {"1152000", B1152000, 1152000},
+#endif
+#ifdef B1500000
+  {"1500000", B1500000, 1500000},
+#endif
+#ifdef B2000000
+  {"2000000", B2000000, 2000000},
+#endif
+#ifdef B2500000
+  {"2500000", B2500000, 2500000},
+#endif
+#ifdef B3000000
+  {"3000000", B3000000, 3000000},
+#endif
+#ifdef B3500000
+  {"3500000", B3500000, 3500000},
+#endif
+#ifdef B4000000
+  {"4000000", B4000000, 4000000},
 #endif
   {NULL, 0, 0}
 };