re PR c++/31809 (sometimes TREE_READONLY is still set for non read only variables causing wrong code)

	PR c++/31809
	* decl.c (cp_finish_decl): Clear TREE_READONLY flag on TREE_STATIC
	variables that need runtime initialization.

	* g++.dg/opt/static5.C: New test.

From-SVN: r125201