ENH: Adding implementation of shared library version support on UNIX. This addresses the feature request described in bug#32.

Modules/CMakeDefaultMakeRuleVariables.cmake

@@ -43,7 +43,7 @@
 # create a shared C++ library
 IF(NOT CMAKE_CXX_CREATE_SHARED_LIBRARY)
   SET(CMAKE_CXX_CREATE_SHARED_LIBRARY
-      "<CMAKE_CXX_COMPILER> <CMAKE_SHARED_LIBRARY_CXX_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
+      "<CMAKE_CXX_COMPILER> <CMAKE_SHARED_LIBRARY_CXX_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_CXX_FLAGS> <CMAKE_SHARED_LIBRARY_SONAME_FLAG><TARGET_SONAME> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
 ENDIF(NOT CMAKE_CXX_CREATE_SHARED_LIBRARY)
 
 # create a c++ shared module copy the shared library rule by default
@@ -54,7 +54,7 @@ ENDIF(NOT CMAKE_CXX_CREATE_SHARED_MODULE)
 # create a C shared library
 IF(NOT CMAKE_C_CREATE_SHARED_LIBRARY)
   SET(CMAKE_C_CREATE_SHARED_LIBRARY
-      "<CMAKE_C_COMPILER> <CMAKE_SHARED_LIBRARY_C_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
+      "<CMAKE_C_COMPILER> <CMAKE_SHARED_LIBRARY_C_FLAGS> <LINK_FLAGS> <CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS> <CMAKE_SHARED_LIBRARY_SONAME_FLAG><TARGET_SONAME> -o <TARGET> <OBJECTS> <LINK_LIBRARIES>")
 ENDIF(NOT CMAKE_C_CREATE_SHARED_LIBRARY)
 
 # create a C shared module just copy the shared library rule