Do not segfault when log file can not be opened.
Do not segfault when log file can not be opened.

If the user visible log file can not be written to, report the problem
to the system log and move on.  This fixes a crash bug in tsdfx (issue
#86).

dag-erling/tsdfx,dag-erling/tsdfx,petterreinholdtsen/tsdfx,petterreinholdtsen/tsdfx,petterreinholdtsen/tsdfx,dag-erling/tsdfx