Use the correct modifier independently of the layer

This reverts commit 49e2eb410b.

menelaus.scm

@@ -297,12 +297,12 @@
     (press-key-aux keycode key)))
 
 ;; Record that a given key being released resulted in a modifier release.
-(define (release-modifier keycode key n)
+(define (release-modifier modifier key n)
   (if (= (or (vector-ref keys-for-modifiers n) (- 0 1)) key)
       (begin
-        (set! modifiers (^ modifiers (unmodify keycode)))
+        (set! modifiers (^ modifiers modifier))
         (vector-set! keys-for-modifiers n #f))
-      (and (< n 7) (release-modifier keycode key (+ n 1)))))
+      (and (< n 7) (release-modifier modifier key (+ n 1)))))
 
 ;; Record a key release, clearing it out of the press tracking data.
 (define (release-key key)
@@ -320,9 +320,7 @@
                 (vector-set! keys-for-frame slot #f))
               #f)
           (if modifier-slot
-              (begin
-                (release-modifier keycode key 0)
-                (release-key key))
+              (release-modifier (call-c-func "mathpow" 2 modifier-slot) key 0)
               #f)))))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; Send USB

usb_keyboard.c

@@ -33,6 +33,9 @@
 int16_t mathlog2(int x) {
   return round(log(x)/log(2));
 }
+int16_t mathpow(int x, int y) {
+  return round(pow(x, y));
+}
 
 /**************************************************************************
  *