Incorrect path for link libraries from PETSc

[Garth Wells]

The correct path is not being added for some link libraries provided by PETSc (specifically, those provided by PCC_LINKER_LIBS).

I see this when building PETSc and DOLFIN using a locally installed OpenMPI. The consequence is that during configuration I get
messages like

 Cannot generate a safe runtime search path for target
  dg-advection-diffusion-demo because files in some directories may conflict
  with libraries in implicit directories:

    runtime library [libmpi_f90.so.0] in /usr/lib may be hidden by files in:
      /home/gnw20/local/lib

[Johannes Ring (johannr)]

I have tried to reproduce this, but without success. What I did was to let Dorsal build OpenMPI, PETSc, and DOLFIN using the attached platform file. I did see some similar warnings like

  CMake Warning at demo/la/eigenvalue/cpp/CMakeLists.txt:31 (add_executable):
    Cannot generate a safe linker search path for target demo_eigenvalue
    because files in some directories may conflict with libraries in implicit
    directories:

      link library [libumfpack.so] in /usr/lib may be hidden by files in:
        /work/johannr/dorsal/Work/FEniCS/lib
      link library [libamd.so] in /usr/lib may be hidden by files in:
        /work/johannr/dorsal/Work/FEniCS/lib

    Some of these libraries may not be found correctly.

but nothing related to OpenMPI and PETSc.

Anyway, these are just CMake warnings and, unless you see some strange behavior, can safely be ignored.

[Garth Wells (garth-wells)]

The issue is that the libs that PETSc supplied 3rd party libs do not use the full path.

I may have partially 'fixed' this a while back by not using as many of the PETSc supplied libs when linking.

[Johannes Ring (johannr)]

The attached patch reduces the number of 3rd party libs for both PETSc and SLEPc to a minimum. This is close to what we had in the SCons based build system. I have tested the patch with several different configurations and will apply it unless someone has any objections.