Fix a compilier error with msys2-mingw64 ( ld.exe: cannot find -ldl ) (#35)

davidwed

2019-09-07 f6437cfaed1dd0acd1ec63e1c282d0e7edfa4522

 CMakeLists.txt

@@ -96,7 +96,9 @@
       include_directories(${DBUS_ARCH_INCLUDE_DIR})
       list(APPEND EXTERNAL_LIBS ${DBUS_LIBRARIES})
   endif(USE_DBUS_IDENTIFIER)    
   list(APPEND EXTERNAL_LIBS dl)
   if(NOT MINGW)
       list(APPEND EXTERNAL_LIBS dl)
   endif(NOT MINGW)
   list(APPEND EXTERNAL_LIBS "-Wl,-Bdynamic")
endif(NOT MSVC)