style: formatting clean up

* data/skeletons/d.m4, examples/d/calc.y, src/output.c,
* src/parse-gram.y:
No tab, no trailing spaces.
Reported by syntax-check.

src/output.c

@@ -236,7 +236,7 @@ prepare_rules (void)
       prhs[r] = i;
       /* RHS of the rule R. */
       for (item_number *rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
-	rhs[i++] = *rhsp;
+        rhs[i++] = *rhsp;
       /* Separator in RHS. */
       rhs[i++] = -1;
 
@@ -245,7 +245,7 @@ prepare_rules (void)
       /* LHS of the rule R. */
       r1[r] = rules[r].lhs->number;
       /* Length of rule R's RHS. */
-      r2[r] = rule_rhs_length(&rules[r]);
+      r2[r] = rule_rhs_length (&rules[r]);
       /* Dynamic precedence (GLR).  */
       dprec[r] = rules[r].dprec;
       /* Merger-function index (GLR).  */

src/parse-gram.y

@@ -462,7 +462,7 @@ tag:
 `-----------------------*/
 
 // A non empty list of possibly tagged symbols for %nterm.
-// 
+//
 // Can easily be defined like symbol_decls but restricted to ID, but
 // using token_decls allows to reudce the number of rules, and also to
 // make nicer error messages on "%nterm 'a'" or '%nterm FOO "foo"'.