Replace error prone signal() with sigaction()

Replace error prone signal() with sigaction()

Up to this date signal() was used which implementation could vary [1].
Sigaction() call is preferred. This commit introduces replacement
from signal() to sigaction() by the use of signal_s() wrapper.
Also remove redundant signal.h header includes.

[1] https://man7.org/linux/man-pages/man2/signal.2.html

Signed-off-by: Lukasz Florczak <lukasz.florczak@linux.intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>