re PR c/15007 (crash when including precompiled header with -include)

	PR 15007
	* c-decl.c (current_file_decl): Rename to all_translation_units,
	adjust comment.
	(pop_scope): If popping file_scope, construct a
	TRANSLATION_UNIT_DECL and make it the context of all the
	symbols in the scope.
	(push_file_scope): Don't construct a TRANSLATION_UNIT_DECL here.
	(pushdecl): Clarify comment.  Do not set DECL_CONTEXT of
	anything to current_file_decl.
	(pushdecl_top_level): Likewise.
	(store_parm_decls_newstyle): Adjust check for nested function.
	(c_write_global_declarations): Update for renamed variable.

From-SVN: r81655