Adapter does not use the same compiler as OpenFAST

[MakisH]

I installed OpenFAST from Spack*, which gave me the following in its CMakeConfig:

# Compilers use by OpenFAST build
set(OpenFAST_CXX_COMPILER "/home/gc/spack/opt/spack/linux-ubuntu22.04-skylake/gcc-11.4.0/openmpi-5.0.3-ecb7njyuqk5aaoxtz3rbkmobkisc5hhp/bin/mpic++")
set(OpenFAST_C_COMPILER "/home/gc/spack/opt/spack/linux-ubuntu22.04-skylake/gcc-11.4.0/openmpi-5.0.3-ecb7njyuqk5aaoxtz3rbkmobkisc5hhp/bin/mpicc")
set(OpenFAST_Fortran_COMPILER "/home/gc/spack/opt/spack/linux-ubuntu22.04-skylake/gcc-11.4.0/openmpi-5.0.3-ecb7njyuqk5aaoxtz3rbkmobkisc5hhp/bin/mpif90")

However, building the adapter with the default CMake options leads to errors finding mpi.h in various dependency source files, since it uses the plain g++ instead of mpic++.

We need a way to get the right compiler that the OpenFAST header expects.

*with some issues and workarounds, I will elaborate on that later.