BuildSystem: Sort out issues with mysql-libraries under *nix (and should now also work properly for Win32)

- Rename the "EXTERNAL_MYSQL" flag to "USE_MYSQL_SOURCES" to reflect it's PROPER use (and ensure that it's ONLY used on Win32)
- Remove a lingering "scripts" definition (the "scripts"-target is always included, but only from compiled parts (broke builds with -DSCRIPTS=0)

--HG--
branch : trunk

src/server/worldserver/CMakeLists.txt

@@ -157,21 +157,15 @@ endif()
 
 set_target_properties(worldserver PROPERTIES LINK_FLAGS "${worldserver_LINK_FLAGS}")
 
-if( SCRIPTS )
-  set(SCRIPT_LIB "scripts")
-else()
-  set(SCRIPT_LIB "")
-endif()
-
 target_link_libraries(worldserver
   game
   shared
+  scripts
   trinitysockets
   collision
   g3dlib
   gsoap
   ${JEMALLOC_LIB}
-  ${SCRIPT_LIB}
   ${READLINE_LIBRARY}
   ${TERMCAP_LIBRARY}
   ${ACE_LIBRARY}