pyiec61850: Use CMAKE_INSTALL_LIBDIR from GNUInstallDirs in cmake

This ensures that it gets installed in platform specified system libdir
all platforms do not use /usr/lib as assumed here e.g. ppc64 uses lib64

Signed-off-by: Khem Raj <raj.khem@gmail.com>

pyiec61850/CMakeLists.txt

@@ -34,7 +34,9 @@ execute_process(
 	OUTPUT_VARIABLE PYTHON_SITE_DIR
 )
 
-install(FILES ${CMAKE_CURRENT_BINARY_DIR}/iec61850.py DESTINATION ${PYTHON_SITE_DIR})
-install(TARGETS _iec61850 LIBRARY DESTINATION ${PYTHON_SITE_DIR})
+include(GNUInstallDirs)
+
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/iec61850.py DESTINATION ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}/python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/site-packages)
+install(TARGETS _iec61850 LIBRARY DESTINATION ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}//python${PYTHON_VERSION_MAJOR}.${PYTHON_VERSION_MINOR}/site-packages)
 
 add_test(test_pyiec61850 ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_LIST_DIR}/test_pyiec61850.py)