Guard remapping logic with MAGIC_ENABLE (#25537)

* Only perform key and mod remapping in keycode_config() and mod_config() when MAGIC_ENABLE is defined.
* If not set, these functions now return the original keycode or modifier unchanged.
* Reduces firmware size, and unnecessary code when MAGIC_ENABLE is not enabled.
* Removed space saving suggestion with magic functions from squeezing AVR documentation

docs/squeezing_avr.md

@@ -87,26 +87,6 @@ Or if you're not using layers at all, you can outright remove the functionality
 #define NO_ACTION_LAYER
 ```
 
-## Magic Functions
-
-There are two `__attribute__ ((weak))` placeholder functions available to customize magic keycodes. If you are not using that feature to swap keycodes, such as backslash with backspace, add the following to your `keymap.c` or user space code:
-```c
-#ifndef MAGIC_ENABLE
-uint16_t keycode_config(uint16_t keycode) {
-    return keycode;
-}
-#endif
-```
-Likewise, if you are not using magic keycodes to swap modifiers, such as Control with GUI, add the following to your `keymap.c` or user space code:
-```c
-#ifndef MAGIC_ENABLE
-uint8_t mod_config(uint8_t mod) {
-    return mod;
-}
-#endif
-```
-Both of them will overwrite the placeholder functions with a simple return statement to reduce firmware size.
-
 ## OLED tweaks
 
 One place you can save a bunch of space here is by not using `sprintf` or `snprintf`. This function call takes up ~1.5kB of firmware space, and can be rewritten. For instance, WPM uses this a lot.

quantum/keycode_config.c

@@ -24,6 +24,7 @@ keymap_config_t keymap_config;
  * and will return the corrected keycode, when appropriate.
  */
 __attribute__((weak)) uint16_t keycode_config(uint16_t keycode) {
+#ifdef MAGIC_ENABLE
     switch (keycode) {
         case KC_CAPS_LOCK:
         case KC_LOCKING_CAPS_LOCK:
@@ -115,6 +116,9 @@ __attribute__((weak)) uint16_t keycode_config(uint16_t keycode) {
         default:
             return keycode;
     }
+#else
+    return keycode;
+#endif // MAGIC_ENABLE
 }
 
 /** \brief mod_config
@@ -124,6 +128,7 @@ __attribute__((weak)) uint16_t keycode_config(uint16_t keycode) {
  */
 
 __attribute__((weak)) uint8_t mod_config(uint8_t mod) {
+#ifdef MAGIC_ENABLE
     /**
      * Note: This function is for the 5-bit packed mods, NOT the full 8-bit mods.
      * More info about the mods can be seen in modifiers.h.
@@ -161,5 +166,6 @@ __attribute__((weak)) uint8_t mod_config(uint8_t mod) {
         mod &= ~MOD_RGUI;
     }
 
+#endif // MAGIC_ENABLE
     return mod;
 }