[svn-r19125] Interrim checkin of AIO VFD mods -- current checkin is NOT fully tested.

Have a reasonable smoke check going for AIO on sec2 -- aio is not tested 
on any other file driver.  Also all tests on Phoenix (AMD 64 / Debian) 
only.  Must test on other platforms as well.

config/linux-gnulibc1

@@ -126,6 +126,14 @@ if test $CC_BASENAME = cmpicc; then
   hdf5_cv_mpi_complex_derived_datatype_works=${hdf5_cv_mpi_complex_derived_datatype_works='no'}
 fi
 
+# Link in real time library to support use of AIO.
+#
+# Note that while the following is correct for gcc, it is may be wrong for
+# other compilers used under Linux.  Will have to test for this and change
+# it if necessary.
+#                                               JRM -- 5/20/10
+LIBS="$LIBS -lrt"
+
 #Comment out the following line if your system supports collective IO when some processes
 #don't have any contributions to IOs.
 hdf5_cv_mpi_special_collective_io_works=${hdf5_cv_mpi_special_collective_io_works='no'}