I guess XBoard is partly to blame, after all. It is the shell that strips
away the
quotes (explaning the different behavior in a file or on the command line),
but I
now concatenate all argv elements (separated by spaces) into a single line,
before subjecting it to the WinBoard argument parser. An empty string
in argv[i] would simply lead to two consecutive spaces in this line,
which will be treated as a single whitespace by the parser.
I already recognize arguments with whitespace in them as special,
'quoting' them with {}, which was a quoting method known to WB,
but AFAIK not to XBoard, and therefore safe. I guess the problem would
be solved by also recognizing the case of an empty-string argument,
and also put that between {}.
I will fix it.
