Fortran line lengths in v2.4.0_emc.3

[AlexanderRichert-NOAA]

I am unable to compile v2.4.0_emc.3 with GCC (I tried with versions 8 and 11) on account of some lines in RSS_Emissivity_Model.f90 being too long (i.e., past the default limit which I think is 132). I'm able to get around it by adding -ffree-line-length-none to CMAKE_Fortran_FLAGS in libsrc/CMakeLists.txt. On a related note, I would suggest allowing CMAKE_Fortran_FLAGS to accommodate user-provided values (from $FFLAGS env variable or by setting -DCMAKE_Fortran_FLAGS=... on the command line). I think doing something like set(CMAKE_Fortran_FLAGS "-g -fbacktrace -fconvert=big-endian ${CMAKE_Fortran_FLAGS}") would have that effect.

[BenjaminTJohnson]

Thanks for the comment. Just as an FYI, there are modules for CRTM v2.4.0 available in HPC stack and Spack stacks.
I agree with your suggestion in principle, it does add user flexibility. However, it makes support much harder if additional flags are being passed in a script / command line and are not captured in the flags file. For now, we'll stick with flags in the files -- you're going to have to re-compile anyway. I'm happy to add the ffree-line-length-none flag to future CRTM versions.