Determining if the Fortran compiler works failed with the following output:
Change Dir: /Users/wkerzend/anaconda3/conda-bld/multinest_1480095789874/work/MultiNest-master/build/CMakeFiles/CMakeTmp

Run Build Command:"/Users/wkerzend/anaconda3/bin/make" "cmTC_ab8c2/fast"
/Users/wkerzend/anaconda3/bin/make -f CMakeFiles/cmTC_ab8c2.dir/build.make CMakeFiles/cmTC_ab8c2.dir/build
make[1]: Entering directory '/Users/wkerzend/anaconda3/conda-bld/multinest_1480095789874/work/MultiNest-master/build/CMakeFiles/CMakeTmp'
Building Fortran object CMakeFiles/cmTC_ab8c2.dir/testFortranCompiler.f.o
/Users/wkerzend/anaconda3/bin/gfortran    -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -mmacosx-version-min=10.7   -c /Users/wkerzend/anaconda3/conda-bld/multinest_1480095789874/work/MultiNest-master/build/CMakeFiles/CMakeTmp/testFortranCompiler.f -o CMakeFiles/cmTC_ab8c2.dir/testFortranCompiler.f.o
Linking Fortran executable cmTC_ab8c2
/Users/wkerzend/anaconda3/conda-bld/multinest_1480095789874/_b_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol/bin/cmake -E cmake_link_script CMakeFiles/cmTC_ab8c2.dir/link.txt --verbose=1
/Users/wkerzend/anaconda3/bin/gfortran     -arch x86_64    -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk -mmacosx-version-min=10.7 CMakeFiles/cmTC_ab8c2.dir/testFortranCompiler.f.o  -o cmTC_ab8c2  
ld: unexpected token: !tapi-tbd-v2 file '/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk/usr/lib/libm.tbd' for architecture x86_64
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_ab8c2.dir/build.make:97: recipe for target 'cmTC_ab8c2' failed
make[1]: *** [cmTC_ab8c2] Error 1
make[1]: Leaving directory '/Users/wkerzend/anaconda3/conda-bld/multinest_1480095789874/work/MultiNest-master/build/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_ab8c2/fast' failed
make: *** [cmTC_ab8c2/fast] Error 2