Rename tcp-functions as they are conflicting with qemu functions

I´m currently writing a new ui Backend for QEMU that enables RDP access via FreeRDP. The tcp-functions are conflicting existing symbols in qemu and both are exported.

So as changing the names within FreeRDP is less complex than changing them in qemu I decided renaming those functions in my fork of FreeRDP.

Please mainstream this change.

Thank you.