Add C file forgotten from last commit

c/util.c

@@ -0,0 +1,38 @@
+#include <sys/types.h>
+
+#include <assert.h>
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <math.h>
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "scheme.h"
+
+void accum_elt(struct accum *accum, value_t elt)
+{
+    value_t newtail;
+
+    newtail = fl_cons(elt, FL_NIL);
+    if (accum->tail != FL_NIL) {
+        cdr_(accum->tail) = newtail;
+    } else {
+        accum->list = newtail;
+    }
+    accum->tail = newtail;
+}
+
+void accum_pair(struct accum *accum, value_t a, value_t d)
+{
+    accum_elt(accum, fl_cons(a, d));
+}
+
+void accum_name_value(struct accum *accum, const char *name, value_t value)
+{
+    accum_pair(accum, string_from_cstr(name), value);
+}