re PR c/529 (-Wshadow warns on function prototypes vs. global vars)

re PR c/529 (-Wshadow warns on function prototypes vs. global vars)

	PR c/529
	* c-decl.c (warn_if_shadowing): Don't check for PARM_DECL in
	nested function declarators.
	(pushdecl): Don't call warn_if_shadowing for PARM_DECL.
	(grokparms): Call warn_if_shadowing for parameters used within the
	parameter list.
	(store_parm_decls_newstyle): Call warn_if_shadowing for parameters
	not used within the parameter list.
	(store_parm_decls_oldstyle): Call warn_if_shadowing for parameters.

testsuite:
	* gcc.dg/Wshadow-3.c: New test.

From-SVN: r102571