Determine Fortran compiler always picks GNU first if available
Even though the philosophy appears to be that proprietary Fortran compilers should be picked first and GNU compilers should be picked last, due to this logic in Modules/CMakeDetermineCompiler.cmake line 17,
# Prefer vendors of compilers from reference languages. foreach(l ${_languages}) list(APPEND CMAKE_${lang}_COMPILER_LIST ${_${lang}_COMPILER_NAMES_${CMAKE_${l}_COMPILER_ID}}) endforeach()
if GNU compilers are selected for C/CXX compilers, gfortran or equivalent will be selected over other proprietary compilers. CMake shouldn't try to prioritize already selected compilers in case there is a more preferable compiler for a different language.