cp_variablesubst() and cp_bquote(), rewrite

src/frontend/parser/backq.c

@@ -37,9 +37,8 @@ cp_bquote(wordlist *wlist)
         while (t < s)
             wbuf[i++] = *t++;
         wbuf[i] = '\0';
-        (void) strcpy(buf, ++s);
+        (void) strcpy(buf, ++t);
         s = buf;
-        t++;
         while (*s && (*s != cp_back)) {
             t++;    /* Get s and t past the next backquote. */
             s++;

src/frontend/variable.c

@@ -691,9 +691,8 @@ cp_variablesubst(wordlist *wlist)
             while (t < s)
                 wbuf[i++] = *t++;
             wbuf[i] = '\0';
-            (void) strcpy(buf, ++s);
+            (void) strcpy(buf, ++t);
             s = buf;
-            t++;
             while (*s && (isalphanum(*s) || strchr(VALIDCHARS, *s))) {
                 /* Get s and t past the end of the var name. */
                 t++;