petsc4py/slepc4py should check for compatible integer types

[Prof Garth Wells]

petsc4py detection does not check that it matches the PETSc installation, e.g. DOLFIN will configure a 32-bit int petsc4py with a 64-bit int PETSc library.

[Jan Blechta]

Generally speaking, this particular petsc4py should be built with that particular PETSc. Maybe by comparing os.path.abspath(petsc4py.get_includes()) with include path obtained by FindPETSc.cmake.

[Chris Richardson]

Fixes Issue #479

→ <<cset 56c79528a391>>

[Jan Blechta]

The same fix should apply to slepc4py.

[Martin Sandve Alnæs]

Removing milestone: 1.6 (automated comment)