I also had the mpif90 error on my El Capitan Macbook, but worked around it by rebuilding the openmpi with the latest brew gcc compilers (GCC 5.2.0). It seems the default configuration provided by Homebrew is built with Apple's compilers (and thus has no wrapper for the mpif90). I put these in my ~/.profile:

export HOMEBREW_CC=gcc-5
export HOMEBREW_CXX=g++-5
export FC=gfortran-5

and rebuilt openmpi via:

brew reinstall openmpi --build-from-source

Firedrake installs successfully, but now I am running into a spatialindex related problem whenever I try to import the firedrake module:

python -c 'from firedrake import *'

Traceback (most recent call last):

  File "<string>", line 1, in <module>

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/__init__.py", line 31, in <module>

    from firedrake.assemble import *

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/assemble.py", line 10, in <module>

    from firedrake import assemble_expressions

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/assemble_expressions.py", line 17, in <module>

    from firedrake import function

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/function.py", line 14, in <module>

    from firedrake import functionspace

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/functionspace.py", line 17, in <module>

    import firedrake.mesh as mesh_t

  File "/Users/justin/Software/firedrake/src/firedrake/firedrake/mesh.py", line 16, in <module>

    import firedrake.spatialindex as spatialindex

ImportError: dlopen(/Users/justin/Software/firedrake/src/firedrake/firedrake/spatialindex.so, 2): Symbol not found: __ZN5Tools11PropertySet11setPropertyENSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEERKNS_7VariantE

  Referenced from: /Users/justin/Software/firedrake/src/firedrake/firedrake/spatialindex.so

  Expected in: flat namespace

 in /Users/justin/Software/firedrake/src/firedrake/firedrake/spatialindex.so

Looks like something went awry with spatialindex. Anyone else having this problem? 

Thanks,

Justin