re PR target/39175 (ICE while compiling qt-4.5.0-rc1)

	PR target/39175
	* c-common.c (c_determine_visibility): If visibility changed and
	DECL_RTL has been already set, call make_decl_rtl to update symbol
	flags.

	* decl2.c (determine_visibility): If visibility changed and
	DECL_RTL has been already set, call make_decl_rtl to update symbol
	flags.

	* gcc.dg/visibility-20.c: New test.
	* g++.dg/ext/visibility/visibility-11.C: New test.

From-SVN: r144305