Cannot do several builds of sfeMovie at the same time

[Ceylo]

Building sfeMovie requires building FFmpeg, which is always done in the path : /tmp/ffmpeg. This causes issues when sfeMovie is being built for several configurations at the same time, because the build process cleans up the directory after it's done. But in case of several parallel builds, the /tmp/ffmpeg may still be used by another build.

Possibles solutions:

• create a unique path based on the target configuration
• create a random path
• ask FFmpeg developers to fix their issues with spaces in paths (which forces us to use this temporary path)