* c.opt (fgnu89-inline): New option.
	* c-opts.c (c_common_post_options): Set default value for
	flag_gnu89_inline.
	* c-decl.c (WANT_C99_INLINE_SEMANTICS): Remove.
	(pop_scope): Check flag_gnu89_inline rather than flag_isoc99 for
	inline functions.
	(diagnose_mismatched_decls, merge_decls, start_decl): Likewise.
	(grokdeclarator, start_function): Likewise.
	* c-cppbuiltin.c (c_cpp_builtins): Define either
	__GNUC_GNU_INLINE__ or __GNUC_STDC_INLINE__.
	* doc/invoke.texi (Option Summary): Mention -fgnu89-inline.
	(C Dialect Options): Document -fgnu89-inline.
	* doc/extend.texi (Function Attributes): Explain what the
	gnu_inline attribute does.
	* doc/cpp.texi (Common Predefined Macros): Document
	__GNUC_GNU_INLINE__ and __GNUC_STDC_INLINE__.

From-SVN: r122565