issue with pthreads and tru64

[Dave Love]

At one stage, building on Tru64 with gcc worked for me, but I just
tried on Tru64 5.1B with gcc 3.2.3 and now it fails.  (pthread.h
checks compiler macros, and doesn't recognize gcc.)  I suspect
previously that the header was fixed, but I haven't been able to check
or determine whether pthreads works with gcc in principle.  In the
meantime, I suggest adding this warning to configure.

*** configure.ac        2003/06/02 12:18:07     1.1
--- configure.ac        2003/06/02 13:33:31
***************
*** 447,452 ****
--- 447,457 ----
          ;;
     osf*)
        AC_DEFINE(OSF)
+       if test "$GCC" = yes; then
+          AC_MSG_WARN([pthreads may not work with GCC under Tru64])
+          AC_MSG_WARN([If you get build errors mentioning PTHREADDEFAULTS 
etc.,])
+          AC_MSG_WARN([re-configure with CC=cc.])
+       fi
          ;;
     irix6*)
        # rtentry is detected OK on a 6.5.19 system.