It is assumed that when installing the `xenocara` package
the `xenocara-xbacklight` package is installed as a dependency.
However with this commit we make sure that it is installed.
Currently the playerctl package signature has expired on Hyperbola Project.
Hyperbola Project is preparing for v0.4 and soon there should be no
such problem. So I temporarily remove playerctl
seccomp (short for secure computing mode) is a computer security facility in the Linux kernel.
seccomp was first devised by Andrea Arcangeli in January 2005 for use in public grid computing
and was originally intended as a means of safely running untrusted compute-bound programs.
It was merged into the Linux kernel mainline in kernel version 2.6.12, which was released on
March 8, 2005. seccomp allows a process to make a one-way transition into a "secure" state
where it cannot make any system calls except exit(), sigreturn(), read() and write() to
already-open file descriptors. Should it attempt any other system calls, the kernel will
terminate the process with SIGKILL or SIGSYS. In this sense, it does not virtualize the
system's resources but isolates the process from them entirely.
