inspect c00.c to see keywords

keywords used in v2 & v3 cc
---------------------------

        init("int", 0);
	init("char", 1);
	init("float", 2);
	init("double", 3);
/*	init("long", 4);  */
	init("auto", 5);
	init("extern", 6);
	init("static", 7);
	init("goto", 10);
	init("return", 11);
	init("if", 12);
	init("while", 13);
	init("else", 14);
	init("switch", 15);
	init("case", 16);
	init("break", 17);
	init("continue", 18);
	init("do", 19);
	init("default", 20);

keywords used in v4
-------------------

c00.c is missing but we know from the existing source code
that for statements were supported

keywords used in v5 cc
----------------------

	"int",		INT,
	"char",		CHAR,
	"float",	FLOAT,
	"double",	DOUBLE,
	"struct",	STRUCT,
	"auto",		AUTO,
	"extern",	EXTERN,
	"static",	STATIC,
	"register",	REG,
	"goto",		GOTO,
	"return",	RETURN,
	"if",		IF,
	"while",	WHILE,
	"else",		ELSE,
	"switch",	SWITCH,
	"case",		CASE,
	"break",	BREAK,
	"continue",	CONTIN,
	"do",		DO,
	"default",	DEFAULT,
	"for",		FOR,
	"sizeof",	SIZEOF,

keywords used in v6 cc
----------------------

	"int",		INT,
	"char",		CHAR,
	"float",	FLOAT,
	"double",	DOUBLE,
	"struct",	STRUCT,
	"long",		LONG,
	"auto",		AUTO,
	"extern",	EXTERN,
	"static",	STATIC,
	"register",	REG,
	"goto",		GOTO,
	"return",	RETURN,
	"if",		IF,
	"while",	WHILE,
	"else",		ELSE,
	"switch",	SWITCH,
	"case",		CASE,
	"break",	BREAK,
	"continue",	CONTIN,
	"do",		DO,
	"default",	DEFAULT,
	"for",		FOR,
	"sizeof",	SIZEOF,

keywords used in v7 cc
----------------------

	"int",		INT,
	"char",		CHAR,
	"float",	FLOAT,
	"double",	DOUBLE,
	"struct",	STRUCT,
	"long",		LONG,
	"unsigned",	UNSIGN,
	"union",	UNION,
	"short",	INT,
	"auto",		AUTO,
	"extern",	EXTERN,
	"static",	STATIC,
	"register",	REG,
	"goto",		GOTO,
	"return",	RETURN,
	"if",		IF,
	"while",	WHILE,
	"else",		ELSE,
	"switch",	SWITCH,
	"case",		CASE,
	"break",	BREAK,
	"continue",	CONTIN,
	"do",		DO,
	"default",	DEFAULT,
	"for",		FOR,
	"sizeof",	SIZEOF,
	"typedef",	TYPEDEF,
	"enum",		ENUM,

keywords used in 2.11BSD cc
---------------------------

	"int",		INT,
	"char",		CHAR,
	"float",	FLOAT,
	"double",	DOUBLE,
	"struct",	STRUCT,
	"long",		LONG,
	"unsigned",	UNSIGN,
	"union",	UNION,
	"short",	INT,
	"void",		VOID,
	"auto",		AUTO,
	"extern",	EXTERN,
	"static",	STATIC,
	"register",	REG,
	"goto",		GOTO,
	"return",	RETURN,
	"if",		IF,
	"while",	WHILE,
	"else",		ELSE,
	"switch",	SWITCH,
	"case",		CASE,
	"break",	BREAK,
	"continue",	CONTIN,
	"do",		DO,
	"default",	DEFAULT,
	"for",		FOR,
	"sizeof",	SIZEOF,
	"typedef",	TYPEDEF,
	"enum",		ENUM,
	"asm",		ASM,