PR24567, assertion failure in ldlang.c:6868 when compiling with -flto
    
    As the existing comment said: "a common ought to be overridden by a
    def in a -flto object".  This patch makes the code actually do that,
    rather than allowing a normal object file common to override a -flto
    defined symbol.
    
    	PR 24567
    	* plugin.c (plugin_notice): Do not let a common symbol override
    	a non-common definition in IR.
    
    (cherry picked from commit af4fa23fba220c1b26bb3c8a7996b406dcc181cc)