cpp: allow vastly more #defines
<inet/tcp.h> requires considerably more defines to preprocess than the
4,000 we previously allowed.  Allow an (equally arbitrary) 16,000
symbols instead.

@@ -263,11 +263,11 @@
 static  char            *strdex(char *, int);
 int             yywrap(void);
 int             main(int argc, char **argav);
 
 
-#define symsiz 4000
+#define symsiz 16000
 static  struct symtab stab[symsiz];
 
 static  struct symtab *defloc;
 static  struct symtab *udfloc;
 static  struct symtab *incloc;