On macos, (#2121)

Use @loader_path for the calling library/executable
Use @rpath for dependent libraries.

CMakeLists.txt

@@ -40,9 +40,14 @@ message(STATUS "NGRAPH_API_VERSION ${NGRAPH_API_VERSION}")
 set(NGRAPH_INCLUDE_PATH
     ${CMAKE_CURRENT_SOURCE_DIR}/src
 )
-# Suppress an OS X-specific warning.
-if (POLICY CMP0042)
-    cmake_policy(SET CMP0042 OLD)
+
+if (APPLE)
+    # Suppress an OS X-specific warning.
+    if (POLICY CMP0042)
+        cmake_policy(SET CMP0042 NEW)
+    else()
+        set(MACOS_RPATH ON)
+    endif()
 endif()
 
 project (ngraph)
@@ -151,10 +156,12 @@ set(NGRAPH_INSTALL_LIB "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
 set(NGRAPH_INSTALL_INCLUDE "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_INCLUDEDIR}")
 set(NGRAPH_INSTALL_DOC "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DOCDIR}")
 set(NGRAPH_INSTALL_BIN "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}")
-if (DEFINED NGRAPH_RPATH)
-    set(CMAKE_INSTALL_RPATH "$ORIGIN:${NGRAPH_RPATH}")
-else()
-    set(CMAKE_INSTALL_RPATH "$ORIGIN")
+if (NOT APPLE)
+    if (DEFINED NGRAPH_RPATH)
+        set(CMAKE_INSTALL_RPATH "$ORIGIN:${NGRAPH_RPATH}")
+    else()
+        set(CMAKE_INSTALL_RPATH "$ORIGIN")
+    endif()
 endif()
 
 #-----------------------------------------------------------------------------------------------

src/ngraph/CMakeLists.txt

@@ -223,6 +223,8 @@ if (NOT APPLE)
     if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
         set_property(TARGET ngraph APPEND_STRING PROPERTY LINK_FLAGS " -Wl,--no-as-needed")
     endif()
+else()
+    set_property(TARGET ngraph APPEND_STRING PROPERTY LINK_FLAGS " -Wl,-rpath,@loader_path")
 endif()
 
 # Defines macro in C++ to load backend plugin

src/tools/nbench/CMakeLists.txt

@@ -21,6 +21,9 @@ set (SRC
 
 add_executable(nbench ${SRC})
 
+if (APPLE)
+    set_property(TARGET nbench APPEND_STRING PROPERTY LINK_FLAGS " -Wl,-rpath,@loader_path/../lib")
+endif()
 target_link_libraries(nbench ngraph)
 if (NGRAPH_CPU_ENABLE)
     target_link_libraries(nbench cpu_backend)