support G_SPAWN_FILE_AND_ARGV_ZERO specifying that the vector passed in to

support G_SPAWN_FILE_AND_ARGV_ZERO specifying that the vector passed in to

2001-06-08  Havoc Pennington  <hp@redhat.com>

	* gspawn.c: support G_SPAWN_FILE_AND_ARGV_ZERO specifying that
	the vector passed in to g_spawn_* contains a filename to
	execute in argv[0] then the actual argv begins at argv + 1.
	Kind of a lame hack, but this isn't something you commonly want
	to do, and avoids adding more function arguments.