Pass on the LD_RUN_PATH environment variable.

This is set by conda build system on Linux.  The patchelf utility
seems to work better when the original binary contains RPATH.

Author: pavoljuhas

SConstruct

@@ -46,7 +46,7 @@ def pyconfigvar(name):
 # copy system environment variables related to compilation
 DefaultEnvironment(ENV=subdictionary(os.environ, '''
     PATH PYTHONPATH GIT_DIR
-    CPATH CPLUS_INCLUDE_PATH LIBRARY_PATH
+    CPATH CPLUS_INCLUDE_PATH LIBRARY_PATH LD_RUN_PATH
     LD_LIBRARY_PATH DYLD_LIBRARY_PATH DYLD_FALLBACK_LIBRARY_PATH
     MACOSX_DEPLOYMENT_TARGET
     '''.split())