Fixed Linux MS/TP 76800 bitrate for Linux 2.6.20+ circa 2007 and added get/set API for config. (#1007)

CMakeLists.txt

@@ -724,6 +724,7 @@ elseif(${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
     $<$<BOOL:${BACDL_ARCNET}>:ports/linux/arcnet.c>
     $<$<BOOL:${BACDL_MSTP}>:ports/linux/rs485.c>
     $<$<BOOL:${BACDL_MSTP}>:ports/linux/rs485.h>
+    $<$<BOOL:${BACDL_MSTP}>:ports/linux/termios2.h>
     $<$<BOOL:${BACDL_MSTP}>:ports/linux/dlmstp.c>
     $<$<BOOL:${BACDL_ETHERNET}>:ports/linux/ethernet.c>
     $<$<BOOL:${BACDL_BSC}>:ports/linux/bsc-event.c>