Added section on threads problems on Reliant UNIX; this relates to

bug #113797.  We should be able to resolve this for the next release.

Reflowed the comments on Monterey (64-bit AIX) to match the flow of the
other platform-specific sections.

README

@@ -386,13 +386,18 @@ OS/2:   If you are running Warp3 or Warp4 and have IBM's VisualAge C/C++
         and type NMAKE.  Threading and sockets are supported by default
         in the resulting binaries of PYTHON15.DLL and PYTHON.EXE.
 
-Monterey (64-bit AIX):
-    The current Monterey C compiler (Visual Age) uses the OBJECT_MODE={32|64}
-    environment variable to set the compilation mode to either 32-bit or
-    64-bit (32-bit mode is the default).  Presumably you want 64-bit
-    compilation mode for this 64-bit OS.  As a result you must first set
-    OBJECT_MODE=64 in your environment before configuring (./configure) or
-    building (make) Python on Monterey.
+Monterey (64-bit AIX): The current Monterey C compiler (Visual Age)
+        uses the OBJECT_MODE={32|64} environment variable to set the
+        compilation mode to either 32-bit or 64-bit (32-bit mode is
+        the default).  Presumably you want 64-bit compilation mode for
+        this 64-bit OS.  As a result you must first set OBJECT_MODE=64
+        in your environment before configuring (./configure) or
+        building (make) Python on Monterey.
+
+Reliant UNIX: The thread support does not compile on Reliant UNIX, and
+        there is a (minor) problem in the configure script for that
+        platform as well.  This should be resolved in time for a
+        future release.
 
 
 Configuring threads