Compilation warning in NWTC_IO.f90

[sayerhs]

Building OpenFAST on Linux with GCC 7.4.0 on ORNL Summit issues the following warning:

[  1%] Building Fortran object modules/nwtc-library/CMakeFiles/nwtclibs.dir/src/NWTC_IO.f90.o
/ccs/proj/cfd142/exawind/exawind-2020-07/source/openfast/modules/nwtc-library/src/NWTC_IO.f90:2248:10:

       USE iso_fortran_env
          1
Warning: Use of the NUMERIC_STORAGE_SIZE named constant from intrinsic module ISO_FORTRAN_ENV at (1) is incompatible with option -fdefault-real-8

OpenFAST commit: 5aacf65

5aacf65c Merge pull request #447 from andrew-platt/f/vc

System information:

sayerhs@login1:~$ lsb_release -d ; uname -a ; gfortran --version
Description:	Red Hat Enterprise Linux Server release 7.6 (Maipo)
Linux login1 4.14.0-115.21.2.el7a.ppc64le #1 SMP Thu May 7 22:22:31 UTC 2020 ppc64le ppc64le ppc64le GNU/Linux
GNU Fortran (GCC) 7.4.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

CMake configure command

cmake 
  -DCMAKE_INSTALL_PREFIX:PATH=/ccs/proj/cfd142/exawind/exawind-2020-07/install/gcc/openfast 
  -DCMAKE_BUILD_TYPE=RELWITHDEBINFO
  -DBUILD_SHARED_LIBS:BOOL=OFF 
  -DFPE_TRAP_ENABLED:BOOL=ON 
  -DUSE_DLL_INTERFACE:BOOL=ON 
  -DBUILD_OPENFAST_CPP_API:BOOL=ON 
  -DYAML_ROOT:PATH=/autofs/nccs-svm1_proj/cfd142/exawind/exawind-2020-07/spack/opt/spack/linux-rhel7-power9le/gcc-7.4.0/yaml-cpp-0.6.2-6gmppkg63e3mubizsarxetpsqavgoqex 
  -DHDF5_ROOT:PATH=/autofs/nccs-svm1_proj/cfd142/exawind/exawind-2020-07/spack/opt/spack/linux-rhel7-power9le/gcc-7.4.0/hdf5-1.10.4-5jqpjwnfoupcjas2fnjbh54t3wkiorq7 
  -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=ON 
  -DCMAKE_INSTALL_RPATH_USE_LINK_PATH:BOOL=ON ..