sdl consumer: Fix potential deadlock (#245)
sdl consumer: Fix potential deadlock (#245)

If the thread might be waiting on the condition variable, signal it
first, and then join
siddharudh/mlt,siddharudh/mlt,j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,j-b-m/mlt,siddharudh/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,siddharudh/mlt,siddharudh/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,siddharudh/mlt