[CMake] CPack Bundle Generator easily hits hdiutil MNAMELEN limit

[Bill Hoffman]

Mike Arthur wrote:
>>From the hdiutil manpage:
> -mountroot path	mount volumes in path instead of in /Volumes.  path must 
> exist.  Note that mountpoint paths must be less than MNAMELEN characters (90 
> as of this writing).
> 
> This limit is easily hit by the mounting of the temporary dmg (tmp.dmg) in the 
> Bundle Generator and causes it to fail.
> 
> May I suggest that, instead of mounting into ./_CPack_Packages/OSX-
> Universal/Bundle/mnt/ instead /tmp/cpackmnt/ is used instead or the mountpoint 
> parameter omitted and the Volumes mountpoint is used instead?
> 
> I can write a patch if necessary but it should be a trivial fix (if agreed).

I am concerned that /tmp/ would not be unique enough, what if two cpacks 
run at the same time?

-Bill