I’m linking a shared library that depends on a large number of third-party libraries. The source for my library is primarily Fortran and the NAG Fortran compiler is being used to do the linking. It’s unique in that it calls gcc rather than ld to do the linking. So to feed arguments to ld through gcc, an unusual syntax is required. For example setting the rpath for the MPI library looks like this:
-Wl,-Wl,,-rpath -Wl,-Wl,,/opt/lib/nag-7_2/mpich/4.2.3/lib
CMake understands how to do all this for the NAG compiler. This all works fine.
I’m now adding a link dependency on a new TPL that itself depends on MPI
target_link_libraries(truchas PUBLIC MUMPS::DMUMPS)
and I’m now getting a link error because of these new additional arguments
-Wl,-rpath -Wl,/opt/lib/nag-7_2/mpich/4.2.3/lib
which are incorrect because it is asking gcc to interpret the -rpath argument.
The find_package(MUMPS) command uses the config method, and I’ve looked at the corresponding config files and I recognize nothing there that would explain the source of these additional arguments. What is responsible for generating these new link line arguments and why are they the appropriate ones for gcc as the linker rather than the NAG Fortran compiler even though all the other link line arguments are correct for the Fortran compiler?