Change CMakeLists.txt for OSX
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c8fac31..0387fc5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -142,6 +142,21 @@
 set(GR_GSM_SWIG_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/swig CACHE INTERNAL "" FORCE)
 
 ########################################################################
+# On Apple only, set install name and use rpath correctly, if not already set
+########################################################################
+if(APPLE)
+    if(NOT CMAKE_INSTALL_NAME_DIR)
+        set(CMAKE_INSTALL_NAME_DIR ${CMAKE_INSTALL_PREFIX}/${GR_LIBRARY_DIR} CACHE PATH "Library Install Name Destination Directory" FORCE)
+    endif(NOT CMAKE_INSTALL_NAME_DIR)
+    if(NOT CMAKE_INSTALL_RPATH)
+        set(cmakE_INSTALL_RPATH  ${CMAKE_INSTALL_PREFIX}/${GR_LIBRARY_DIR} CACHE PATH "Library Install RPath" FORCE)
+    endif(NOT CMAKE_INSTALL_RPATH)
+    if(NOT CMAKE_BUILD_WITH_INSTALL_RPATH)
+        set(CMAKE_BUILD_WITH_INSTALL_RPATH ON CACHE  BOOL "Do Build Using Library Install RPath" FORCE)
+    endif(NOT CMAKE_BUILD_WITH_INSTALL_RPATH)
+endif(APPLE)
+
+########################################################################
 # Create uninstall target
 ########################################################################
 configure_file(