jl.config errors out at assert(exist(jlhome, 'dir') == 7)

I just did a fresh clone of the mexjulia master and am running

Julia Version 0.5.1-pre+4
Commit 887ad05 (2016-10-28 19:39 UTC)
Platform Info:
  System: Darwin (x86_64-apple-darwin15.6.0)
  CPU: Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Haswell)
  LAPACK: libopenblas64_
  LIBM: libopenlibm
  LLVM: libLLVM-3.7.1 (ORCJIT, haswell)

Inside mexjulia, I have

>> ls
LICENSE     doc     jl      jldict.mat  jlget.m     jlset.m
README.md   examples    jl.m        jleval.m    jlinclude.m mexjulia.cpp

So when I attempt to run Jl.build as per the ReadMe, I get

>> Jl.build
Undefined variable "Jl" or class "Jl.build".

Realizing I was probably not up to date with the latest install process, I followed the first suggestion for closed comment #31: I tried jl.config, selecting my julia executable and got

>> jl.config
Error using jl.config (line 116)
Assertion failed.

Taking a closer look at line 115, I have

>> jl.eval_with_exe('unsafe_string(Base.JLOptions().julia_home)')

ans =

WARNING: Error during initialization of module GMP:
ErrorException("The dynamically loaded GMP library (version 4.2.1 with __gmp_bits_per_limb == 64)
does not correspond to the compile time version (version 6.1.0 with __gmp_bits_per_limb == 64).
Please rebuild Julia.")
/Users/y9KAaixxegjR/Documents/Current_works/julia/usr/bin

juliamatlab / mexjulia

jl.config errors out at assert(exist(jlhome, 'dir') == 7) #33