Split C/Fortran netCDF installations may fail with multiple include directories

[rcabell]

Expected Behavior

Using nc-config in ./configure should include both C and Fortran netCDF include directories.

Current Behavior

Only nc-config --includedir is used, which only finds the netCDF-C include directory. In a combined-include installation, this works fine, but if the netCDF library installation tree is rooted elsewhere (as it is in some module systems, and in Homebrew on Macs), this will fail and required manually defining $NETCDF_INC.

Possible Solution

Use nc-config --fflags to get Fortran-specific include directories and append them to the macros file.

Steps to Reproduce (for bugs)

1. Build on a system with split C/Fortran netCDF library trees
2. Try to build without manually defining $NETCDF_INC and $NETCDF_LIB
3. ????
4. Sad panda

Notes:

I'm not sure if/how this is handled in CMake, but it's worth looking into. Unfortunately, the CI system still uses the legacy build system.