cmake: set INSTALL_RPATH for python on linux

ref. stack-of-tasks/eigenpy#241

Author: nim65s

python/CMakeLists.txt

@@ -3,7 +3,7 @@
 #
 
 # --- LIBRARY --- #
-SET(PYWRAP ${PROJECT_NAME}_pywrap) 
+SET(PYWRAP ${PROJECT_NAME}_pywrap)
 SET(PYWRAP ${PYWRAP} PARENT_SCOPE)
 
 MAKE_DIRECTORY("${${PROJECT_NAME}_BINARY_DIR}/python/${PROJECT_NAME}")
@@ -27,16 +27,20 @@ ELSE()
 ENDIF()
 
 SET_TARGET_PROPERTIES(${PYWRAP}
-  PROPERTIES 
+  PROPERTIES
   PREFIX ""
   SUFFIX ${PYTHON_EXT_SUFFIX}
   OUTPUT_NAME "${PROJECT_NAME}"
   LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/python/${PROJECT_NAME}"
   )
 
+IF(UNIX AND NOT APPLE)
+  SET_TARGET_PROPERTIES(${PYWRAP} PROPERTIES INSTALL_RPATH "\$ORIGIN/../../..")
+ENDIF()
+
 INSTALL(TARGETS ${PYWRAP} DESTINATION ${${PYWRAP}_INSTALL_DIR})
 
-# --- INSTALL SCRIPTS 
+# --- INSTALL SCRIPTS
 SET(PYTHON_FILES
   __init__.py
   )
@@ -47,4 +51,3 @@ FOREACH(python ${PYTHON_FILES})
     "${CMAKE_CURRENT_SOURCE_DIR}/pycppad/${python}"
     DESTINATION ${${PYWRAP}_INSTALL_DIR})
 ENDFOREACH(python)
-