configure incorrectly approves system mkstemp on Tru64 os

[Danny Levinson]

Configure only tests to see if it can create up to 30 temp files using 
the system mkstemp.  (Ref: in coreutils-5.0, configure, line 27177 or 
aclocal.m4, line 3463).  However, the system mkstemp in Tru64 unix will 
only create up to 32 temp files per process.  See for example:

http://www.ornl.gov/its/archives/mailing-lists/tru64-unix-managers/2001/08/msg00307.html

A symptom of this problem is the error message "cannot create temporary 
file" when trying to sort large files on a system where dataspace 
limitations require the creation of many temporary files.  See for 
example the problem reported by Frank Parkin a year ago:

http://www.mail-archive.com/address@hidden/msg00892.html

Changing the test in configure to look at, say, 36 files causes the 
coreutils version of mkstemp to be used in preference to the Tru64 
version and eliminates the problem.

Side note: the reason that even a large Tru64 system will only create 
small temp files may be that the soft or user limits (in particular, the 
datasize limit) are, by default, set much smaller than the hard or 
system limits.  Faster sorts can be achieved by adjusting these up using 
the shell limit or ulimit command.

Thanks for the excellent work,

-- danny levinson