by bbrox@bbrox.org / lionel.ulmer@free.fr.
This adds a configure check and if all goes well turns on the
PTHREAD_SCOPE_SYSTEM thread attribute for new threads.
This should remove the need to add tiny sleeps at the start of threads
to allow other threads to be scheduled.
support on Linux (and Solaris, I expect) for real.
The necessary symbols are defined once and for all,
under the assumption that they won't harm elsewhere.
I believe this works on Linux (tested both on a system with large file
support and one without it), and it may work on Solaris 2.7.
The changes are twofold:
(1) The configure script now boldly tries to set the two symbols that
are recommended (for Solaris and Linux), and then tries a test
script that does some simple seeking without writing.
(2) The _portable_{fseek,ftell} functions are a little more systematic
in how they try the different large file support options: first
try fseeko/ftello, but only if off_t is large; then try
fseek64/ftell64; then try hacking with fgetpos/fsetpos.
I'm keeping my fingers crossed. The meaning of the
HAVE_LARGEFILE_SUPPORT macro is not at all clear.
I'll see if I can get it to work on Windows as well.
