* toplev.c (documented_lang_options): Add -fshort-wchar.
	* c-decl.c (c_decode_option): Likewise.
	(init_decl_processing): If -fshort-wchar, use 'short unsigned int'
	for wchar_t.
	* c-common.c, c-lex.c: Get WCHAR_TYPE_SIZE from wchar_type_node.
	* gcc.c (default_compilers): If -fshort-wchar,
	override __WCHAR_TYPE__.
	* tm.texi (C Dialect Options): Add -fshort-wchar.

From-SVN: r29638