* Make filename const in filesink
* Sine generation returns the next phase
* Avoid malloc/free in radio class
* Implement Tx gain in ZMQ
* Initial ratio RT gain test
* UHD: use timed Tx gain commands to align changes to subframes
* Minor improvement in test_radio_rt_gain
* Fix compilation
* Check RF gain thread id before joining
* Remove redundant zero initialization.
Co-authored-by: Fabian Eckermann <fabian@srs.io>