version the .so

Index: mdal/CMakeLists.txt
--- mdal/CMakeLists.txt.orig
+++ mdal/CMakeLists.txt
@@ -165,6 +165,11 @@ IF (BUILD_SHARED OR ENABLE_TESTS)
   ENDIF(WIN32)
 ENDIF (BUILD_SHARED OR ENABLE_TESTS)
 
+set_target_properties(mdal PROPERTIES
+  VERSION ${LIBmdal_VERSION}
+  SOVERSION ${LIBmdal_VERSION}
+)
+
 # LINK
 FOREACH(LIB_NAME ${MDAL_LIBS})
   TARGET_INCLUDE_DIRECTORIES(${LIB_NAME}
