Make use of standard variables for installation

otherwise %cmake rpm macros will not be able to install things to
the right places.

Author: watologo1

CMakeLists.txt

@@ -14,6 +14,16 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/lib)
 
+if(NOT DEFINED INCLUDE_INSTALL_DIR)
+  set(INCLUDE_INSTALL_DIR include)
+endif()
+if(NOT DEFINED CMAKE_INSTALL_BINDIR)
+  set(CMAKE_INSTALL_BINDIR bin)
+endif()
+if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
+  set(CMAKE_INSTALL_LIBDIR lib)
+endif()
+
 set(CMAKE_C_FLAGS_DEBUG "-D_DEBUG")
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}")
@@ -97,10 +107,10 @@ if(CZMQ_FOUND)
 endif()
 
 install(TARGETS redfishtest redfish
-        RUNTIME DESTINATION bin
-        LIBRARY DESTINATION lib)
-install(FILES ${REDFISH_HDR_PUBLIC_RED} DESTINATION include)
-install(FILES ${REDFISH_HDR_PUBLIC_ENTITIES} DESTINATION include/entities)
+        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
+        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}")
+install(FILES ${REDFISH_HDR_PUBLIC_RED} DESTINATION "${INCLUDE_INSTALL_DIR}")
+install(FILES ${REDFISH_HDR_PUBLIC_ENTITIES} DESTINATION "${INCLUDE_INSTALL_DIR}/entities")
 
 ENABLE_TESTING()