hdf5_ep

[svn-r5727] Purpose:
    Porting to AIX 5.x
Description:
These have been tested out in v1.4.  Folding them in here.
    aclocal.m4:
	Snow's names were not included in the special hack.
	Added its names in.
	Removed the trailing * in pacific.llnl.gov too.
    configure.in:
    fortran/configure.in:
	Added a case to group all AIX 5.* versions as aix5.x.  This allows
	them to share one common config/*aix5.x file.
    configure:
    fortran/configure:
	Derived from configure.in (done in eirene).
    config/powerpc-ibm-aix4.x:
	Added a comment explaining why not to cache sizeof size_t and off_t
    fortran/config/powerpc-ibm-aix4.x:
	Turned of cache of sizeof size_t and off_t because they are depedent
	on compiler options.
    config/powerpc-ibm-aix5.x:
    fortran/config/powerpc-ibm-aix5.x:
	New config file for AIX 5.X
Platforms tests:
    LLNL Blue, Frost, Snow, both serial and parallel.