Update mac build to ease the rpath issues

Summary:
TSIA - for rationale, see comments.
Closes #272

Differential Revision: D4905583

Pulled By: Yangqing

fbshipit-source-id: f6cdbc6b51512da03a4aec3f53de720d35c948b6

CMakeLists.txt

@@ -33,6 +33,7 @@ endfunction(prepend)
 
 # ---[ CMake scripts + modules
 list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/Modules)
+set(CMAKE_MACOSX_RPATH 1)
 
 enable_testing()
 

caffe2/CMakeLists.txt

@@ -161,6 +161,17 @@ if (BUILD_PYTHON)
   target_link_libraries(
       caffe2_pybind11_state ${Caffe2_MAIN_LIBS} ${Caffe2_DEPENDENCY_LIBS}
       ${Caffe2_PYTHON_DEPENDENCY_LIBS})
+  # Add rpath to the python target, so that we will be able to load it. This
+  # is in order to ease the problem of anaconda's ipython DYLD bug, detailed
+  # here:
+  #     https://github.com/BVLC/caffe/issues/2720
+  #     https://github.com/ipython/ipython/issues/8878
+  if (APPLE)
+    add_custom_command(
+        TARGET caffe2_pybind11_state POST_BUILD
+        COMMAND install_name_tool -add_rpath ${CMAKE_INSTALL_PREFIX}/lib
+                $<TARGET_FILE:caffe2_pybind11_state>)
+  endif()
   install(
       TARGETS caffe2_pybind11_state DESTINATION
       ${CMAKE_INSTALL_PREFIX}/caffe2/python)
@@ -180,6 +191,12 @@ if (BUILD_PYTHON)
     target_link_libraries(
         caffe2_pybind11_state_gpu ${Caffe2_MAIN_LIBS} ${Caffe2_DEPENDENCY_LIBS}
         ${Caffe2_PYTHON_DEPENDENCY_LIBS})
+    if (APPLE)
+      add_custom_command(
+          TARGET caffe2_pybind11_state_gpu POST_BUILD
+          COMMAND install_name_tool -add_rpath ${CMAKE_INSTALL_PREFIX}/lib
+                  $<TARGET_FILE:caffe2_pybind11_state_gpu>)
+    endif()
     install(
         TARGETS caffe2_pybind11_state_gpu DESTINATION
         ${CMAKE_INSTALL_PREFIX}/caffe2/python)