DEV-34837: Allow Mac SL executable to find libllcommon.dylib in app bundle's

Resources subdir without requiring user to explicitly set DYLD_LIBRARY_PATH.
Engage the SHARED_LIB_STAGING_DIR mechanism for Mac as well as Windows and
Linux so unit-test executables, too, can find libllcommon.dylib. Perform the
POST_BUILD copy of libllcommon.dylib to SHARED_LIB_STAGING_DIR everywhere but
Windows -- but make it conditional on SHARED_LIB_STAGING_DIR.

indra/cmake/Linking.cmake

@@ -19,6 +19,7 @@ if (NOT STANDALONE)
     set(ARCH_PREBUILT_DIRS_RELEASE ${LIBS_PREBUILT_DIR}/${LL_ARCH_DIR}/lib_release)
     set(ARCH_PREBUILT_DIRS ${ARCH_PREBUILT_DIRS_RELEASE})
     set(ARCH_PREBUILT_DIRS_DEBUG ${ARCH_PREBUILT_DIRS_RELEASE})
+    set(SHARED_LIB_STAGING_DIR ${CMAKE_BINARY_DIR}/sharedlibs CACHE FILEPATH "Location of staged DLLs")
   endif (WINDOWS)
 endif (NOT STANDALONE)
 

indra/llcommon/CMakeLists.txt

@@ -244,22 +244,28 @@ if(LLCOMMON_LINK_SHARED)
         # llcommon.dll get written to the DLL staging directory.
         # Also this directory is shared with RunBuildTest.cmake, y'know, for the tests.
         set_target_properties(llcommon PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${SHARED_LIB_STAGING_DIR})
-    endif(SHARED_LIB_STAGING_DIR)
-
-    if(LINUX)
-        get_target_property(LLCOMMON_PATH llcommon LOCATION)
-        get_filename_component(LLCOMMON_FILE ${LLCOMMON_PATH} NAME)
-        add_custom_command(
+        if(NOT WINDOWS)
+          get_target_property(LLCOMMON_PATH llcommon LOCATION)
+          get_filename_component(LLCOMMON_FILE ${LLCOMMON_PATH} NAME)
+          add_custom_command(
             TARGET llcommon POST_BUILD
             COMMAND ${CMAKE_COMMAND}
             ARGS
               -E
               copy_if_different
-              ${LLCOMMON_FILE}
+              ${LLCOMMON_PATH}
               ${SHARED_LIB_STAGING_DIR}/${CMAKE_CFG_INTDIR}/${LLCOMMON_FILE}
             COMMENT "Copying llcommon to the staging folder."
             )
-    endif(LINUX)
+        endif(NOT WINDOWS)
+    endif(SHARED_LIB_STAGING_DIR)
+
+    if (DARWIN)
+      set_target_properties(llcommon PROPERTIES
+        BUILD_WITH_INSTALL_RPATH 1
+        INSTALL_NAME_DIR "@executable_path/../Resources"
+        )
+    endif(DARWIN)
 
 else(LLCOMMON_LINK_SHARED)
     add_library (llcommon ${llcommon_SOURCE_FILES})