sclang: fix sign issue of net address

fixes #930

Signed-off-by: Tim Blechmann <tim@klingt.org>
sclang: remove unused header file

Signed-off-by: Tim Blechmann <tim@klingt.org>
cmake build system: add option to enable glibc's _FORTIFY_SOURCE macro

Signed-off-by: Tim Blechmann <tim@klingt.org>