Added error if Fortran's default real is double precision. If it is and HL is being built then configure returns an error. This is due to HDFFV-889.

Tested: jam with intel and -r8 flag, both with and without --disable-hl.





git-svn-id: https://svn.hdfgroup.uiuc.edu/hdf5/trunk@25477 dab4d1a6-ed17-0410-a064-d1ae371a2980