FFmpeg утверждает, что OpenSSL несовместим с GPL v3?

Нет, опция -lsдля xtermне принимает аргумент, она просто указывает, что запускаемая xtermоболочка должна быть оболочкой входа в систему.

Вот полный раздел о флаге -lsс выделенной частью, относящейся к вашей проблеме:

   -ls     This option indicates that the shell that is started in the
           xterm window will be a login shell (i.e., the first character
           of argv[0] will be a dash, indicating to the shell that it
           should read the user's.login or.profile).

           The -ls flag and the loginShell resource are ignored if -e is
           also given, because xterm does not know how to make the shell
           start the given command after whatever it does when it is a
           login shell - the user's shell of choice need not be a Bourne
           shell after all.  Also, xterm -e is supposed to provide a
           consistent functionality for other applications that need to
           start text-mode programs in a window, and if loginShell were
           not ignored, the result of ~/.profile might interfere with
           that.

           If you do want the effect of -ls and -e simultaneously, you may
           get away with something like

               xterm -e /bin/bash -l -c "my command here"

           Finally, -ls is not completely ignored, because xterm -ls -e
           does write a /var/run/wtmp entry (if configured to do so),
           whereas xterm -e does not.