Make SAFE_* calls more informative when failing

The output has been "standardized" into the following format:
<file>:<line>: <func>(<params>) <error message>

E.g.:
test.c:130: chdir(mydir) failed

This will then be followed by the usual errno stuff if applicable.

Also includes a few fixes and coding style unification.

Signed-off-by: Mats Liljegren <mats.liljegren@enea.com>
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>