whenever a process writes a cell to disk, it immediately releases the
file lock it had on that cell, which is clearly not the intent of file
locking. Fixed this issue. On a related topic, revised the "cellname
writeable" command so that it can make a cell editable even if the cell
has an advisory lock and cannot be made writeable. Perhaps there should
be a clearer distinction here between "writeable" and "editable". Also:
Reconsidered the previous commit, which removed the "--disable-locking"
from the configuration options. Because some operating systems may not
implement fnctl()-based file locking (Cygwin, for one, apparently doesn't),
it is still useful to be able to completely remove the function, in case
the operating system will fail to recognize the fnctl() values in the
code. Now, file locking behavior can be permanently removed through the
configuration option, or temporarily disabled from the command line.
1bb4cb92ea