xpressn.c: reduce number of (forbidden) keywords

to what is actually used

src/frontend/numparam/numparam.h

@@ -16,7 +16,7 @@ typedef enum {Nodekey = '#'} _nNodekey;  /* Introduces node symbol */
 typedef enum {Intro   = '&'} _nIntro;    /* Introduces preprocessor tokens */
 typedef enum {Comment = '*'} _nComment;  /* Spice Comment lines */
 typedef enum {Psp     = '{'} _nPsp;      /* Ps expression */
-typedef enum {Defd    = 15} _nDefd;      /* serial numb. of 'defined' keyword.
+typedef enum {Defd    = 6} _nDefd;      /* serial numb. of 'defined' keyword.
                                             The others are not used (yet) */
 
 typedef char *auxtable;         /* dummy */

src/frontend/numparam/xpressn.c

@@ -88,8 +88,7 @@ initkeys(void)
 {
     spice_dstring_init(&keyS);
     scopy_up(&keyS,
-             "and or not div mod if else end while macro funct defined"
-             " include for to downto is var");
+             "and or not div mod defined");
     scopy_up(&fmathS,
              "sqr sqrt sin cos exp ln arctan abs pow pwr max min int log sinh cosh"
              " tanh ternary_fcn v agauss sgn gauss unif aunif limit ceil floor");