fix operator table overflow causing hangs and wierd behavior
as reported on 9fans.  example code follows.  it is quite rude,
but the point of cpp is to handle rude code.

(i also deleted some unused code.)

#if (' ' == 32) && ('!' == 33) && ('"' == 34) && ('#' == 35) \
    && ('%' == 37) && ('&' == 38) && ('\'' == 39) && ('(' == 40) \
    && (')' == 41) && ('*' == 42) && ('+' == 43) && (',' == 44) \
    && ('-' == 45) && ('.' == 46) && ('/' == 47) && ('0' == 48) \
    && ('1' == 49) && ('2' == 50) && ('3' == 51) && ('4' == 52) \
    && ('5' == 53) && ('6' == 54) && ('7' == 55) && ('8' == 56) \
    && ('9' == 57) && (':' == 58) && (';' == 59) && ('<' == 60) \
    && ('=' == 61) && ('>' == 62) && ('?' == 63) && ('A' == 65) \
    && ('B' == 66) && ('C' == 67) && ('D' == 68) && ('E' == 69) \
    && ('F' == 70) && ('G' == 71) && ('H' == 72) && ('I' == 73) \
    && ('J' == 74) && ('K' == 75) && ('L' == 76) && ('M' == 77) \
    && ('N' == 78) && ('O' == 79) && ('P' == 80) && ('Q' == 81) \
    && ('R' == 82) && ('S' == 83) && ('T' == 84) && ('U' == 85) \
    && ('V' == 86) && ('W' == 87) && ('X' == 88) && ('Y' == 89) \
    && ('Z' == 90) && ('[' == 91) && ('\\' == 92) && (']' == 93) \
    && ('^' == 94) && ('_' == 95) && ('a' == 97) && ('b' == 98) \
    && ('c' == 99) && ('d' == 100) && ('e' == 101) && ('f' == 102) \
    && ('g' == 103) && ('h' == 104) && ('i' == 105) && ('j' == 106) \
    && ('k' == 107) && ('l' == 108) && ('m' == 109) && ('n' == 110) \
    && ('o' == 111) && ('p' == 112) && ('q' == 113) && ('r' == 114) \
    && ('s' == 115) && ('t' == 116) && ('u' == 117) && ('v' == 118) \
    && ('w' == 119) && ('x' == 120) && ('y' == 121) && ('z' == 122) \
    && ('{' == 123) && ('|' == 124) && ('}' == 125) && ('~' == 126)
/* The character set is ASCII or one of its variants or extensions, not EBCDIC.
   Testing the value of '\n' and '\r' is not relevant.  */
#define C_CTYPE_ASCII 1
#endif

#include <stdbool.h>

Reference: /n/sources/patch/applied/cppbigif
Date: Tue Jul 26 03:40:53 CES 2011
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/cpp/eval.c	Tue Jul 26 03:40:43 2011
+++ /sys/src/cmd/cpp/eval.c	Tue Jul 26 03:40:42 2011
@@ -2,7 +2,7 @@
 #include <libc.h>
 #include "cpp.h"
 
-#define	NSTAK	32
+#define	NSTAK	1024
 #define	SGN	0
 #define	UNS	1
 #define	UND	2
@@ -92,8 +92,8 @@
 
 int	evalop(struct pri);
 struct	value tokval(Token *);
-struct value vals[NSTAK], *vp;
-enum toktype ops[NSTAK], *op;
+struct value vals[NSTAK + 1], *vp;
+enum toktype ops[NSTAK + 1], *op;
 
 /*
  * Evaluate an #if #elif #ifdef #ifndef line.  trp->tp points to the keyword.
@@ -122,6 +122,8 @@
 	op = ops;
 	*op++ = END;
 	for (rand=0, tp = trp->bp+ntok; tp < trp->lp; tp++) {
+		if(op >= ops + NSTAK)
+			sysfatal("cpp: can't evalute #if: increase NSTAK");
 		switch(tp->type) {
 		case WS:
 		case NL:
--- /sys/src/cmd/cpp/lex.c	Tue Jul 26 03:40:46 2011
+++ /sys/src/cmd/cpp/lex.c	Tue Jul 26 03:40:45 2011
@@ -45,8 +45,6 @@
 	S_STNL, S_COMNL, S_EOFCOM, S_COMMENT, S_EOB, S_WS, S_NAME
 };
 
-int	tottok;
-int	tokkind[256];
 struct	fsm {
 	int	state;		/* if in this state */
 	uchar	ch[4];		/* and see one of these characters */