pthreads under linux-x86 uses a silly hack to determine which 
thread is currently running--it examines the high bits of the 
current stack address.  Since pthreads allocates thread stacks
at certain carefully-chosen addresses, this is a fast and easy 
way to determine the currently running thread.

Unfortunately, Charm++'s user-level threads (Cth's) allocate 
their own stacks, which completely derails this process.
Hence to use user-level threads under Linux pthreads (used by
the net-linux-smp version), we need a special hack.
We distribute a slightly modified version of libpthread.a
which determines the currently running thread by looking up
the process ID; this is a bit slower but certainly works.

The only problem is building the patched version of pthread.a:
Linux distributions use several different versions of glibc,
and each requires the corresponding libpthreads.a.

2.0.7  Redhat 5
2.1.1  Redhat 6.0
2.1.3  Redhat 6.2, Slackware 7.1, Debian 2.2, SuSE 7.0 
2.2    RedHat 7, SuSE 7.1 
2.2.5  RedHat 7.3

To build the patched version of pthreads.a for, e.g., glibc 2.2.5, 
use the shell script build_pthreads.sh, which is called like this:

	> ./build_pthreads.sh 2.2.5

The script will take a long time and a lot of disk space to 
run--it should probably only be done by Charm++ developers.
Normal users download the proper libpthread.a for their glibc version
from http://charm.cs.uiuc.edu/distrib/libpthread-$ver.a (or .uu).
The configure script does this version check and downloading.

  Orion Sky Lawlor, olawlor@acm.org, 8/23/2002
