the gnulib strerror_r() is XSI-compliant

Previous commit did not quite work.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
build-sys: systemd uses on library

Since systemd v209 the libsystemd-daemon and libsystemd-journal have been
delivered as single library.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
reorganize .gitignore

First regular expressions, then directories, finally files.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>