Add note about the Intel 12.1 compilers.

This commit was SVN r25854.

README

@@ -247,6 +247,13 @@ Compiler Notes
   platform/compiler combination.  The only effect that this should
   have is that the MCA parameter mpi_leave_pinned will be inoperative.
 
+- Early versions of the Intel 12.1 Linux compiler suite on x86_64 seem
+  to have a bug that prevents Open MPI from working.  Symptoms
+  including immediate segv of the wrapper compilers (e.g., mpicc) and
+  MPI applications.  As of 1 Feb 2012, if you upgrade to the latest
+  version of the Intel 12.1 Linux compiler suite, the problem will go
+  away.
+
 - Early versions of the Portland Group 6.0 compiler have problems
   creating the C++ MPI bindings as a shared library (e.g., v6.0-1).
   Tests with later versions show that this has been fixed (e.g.,