use CMAKE_INSTALL_FULL_LIBDIR in OpenBSD RPATH setting.

also remove the duplicate setting of CMAKE_INSTALL_RPATH

CMakeLists.txt

@@ -87,24 +87,23 @@ IF (UNIX)
     )
 ENDIF()
 
+### See:  http://www.cmake.org/Wiki/CMake_RPATH_handling
 IF (SYS_OPENBSD)
-    # Set RPATH for OpenBSD so WildMIDI can find libWildMidi.so
     # use, i.e. don't skip the full RPATH for the build tree
     SET(CMAKE_SKIP_BUILD_RPATH FALSE)
 
     # when building, don't use the install RPATH already
     # (but later on when installing)
     SET(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)
-    SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
 
     # add the automatically determined parts of the RPATH
     # which point to directories outside the build tree to the install RPATH
     SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
 
     # the RPATH to be used when installing, but only if it's not a system directory
-    LIST(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib" isSystemDir)
+    LIST(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES ${CMAKE_INSTALL_FULL_LIBDIR} isSystemDir)
     IF ("${isSystemDir}" STREQUAL "-1")
-        SET(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
+        SET(CMAKE_INSTALL_RPATH ${CMAKE_INSTALL_FULL_LIBDIR})
     ENDIF()
 ENDIF()