Fix compile issues related to NO_ACTION_MACRO/FUNCTION and LTO_ENABLE (#8663)

* Define NO_ACTION_MACRO/FUNCTION in header instead of makefile when LTO is enabled

Currently, boards and keymaps that define NO_ACTION_MACRO/FUNCTION unconditionally
will not compile with LTO_ENABLE (#8604). This fixes the issue by moving the
definitions from common.mk to action.h, which enables us to check for previous
definitions of those macros (this cannot be done in a makefile).

* Remove LTO checks in templates

Since now NO_ACTION_MACRO/FUNCTION are defined as needed in action.h (which is
included by quantum.h), checking for LTO in keyboard and user code is no
longer required.

* Update LTO_ENABLE docs

5 files changed, 20 insertions, 15 deletions

diff --git a/docs/config_options.md b/docs/config_options.md
index 661cfccce..16fea83a3 100644
--- a/docs/config_options.md
+++ b/docs/config_options.md
@@ -115,9 +115,9 @@ If you define these options you will disable the associated feature, which can s
 * `#define NO_ACTION_ONESHOT`
   * disable one-shot modifiers
 * `#define NO_ACTION_MACRO`
-  * disable old style macro handling: MACRO() & action_get_macro
+  * disable old-style macro handling using `MACRO()`, `action_get_macro()` _(deprecated)_
 * `#define NO_ACTION_FUNCTION`
-  * disable calling of action_function() from the fn_actions array (deprecated)
+  * disable old-style function handling using `fn_actions`, `action_function()` _(deprecated)_
 
 ## Features That Can Be Enabled
 
@@ -317,10 +317,10 @@ This is a [make](https://www.gnu.org/software/make/manual/make.html) file that i
 * `LAYOUTS`
   * A list of [layouts](feature_layouts.md) this keyboard supports.
 * `LINK_TIME_OPTIMIZATION_ENABLE`
-  * Enables Link Time Optimization (`LTO`) when compiling the keyboard.  This makes the process take longer, but can significantly reduce the compiled size (and since the firmware is small, the added time is not noticeable).  However, this will automatically disable the old Macros and Functions features automatically, as these break when `LTO` is enabled.
-  It does this by automatically defining `NO_ACTION_MACRO` and `NO_ACTION_FUNCTION`
+  * Enables Link Time Optimization (LTO) when compiling the keyboard.  This makes the process take longer, but it can significantly reduce the compiled size (and since the firmware is small, the added time is not noticeable).
+However, this will automatically disable the legacy TMK Macros and Functions features, as these break when LTO is enabled.  It does this by automatically defining `NO_ACTION_MACRO` and `NO_ACTION_FUNCTION`.  (Note: This does not affect QMK [Macros](feature_macros.md) and [Layers](feature_layers.md).)
 * `LTO_ENABLE`
-  * It has the same meaning as LINK_TIME_OPTIMIZATION_ENABLE.  You can use `LTO_ENABLE` instead of `LINK_TIME_OPTIMIZATION_ENABLE`.
+  * Has the same meaning as `LINK_TIME_OPTIMIZATION_ENABLE`.  You can use `LTO_ENABLE` instead of `LINK_TIME_OPTIMIZATION_ENABLE`.
 
 ## AVR MCU Options
 * `MCU = atmega32u4`
diff --git a/quantum/template/avr/config.h b/quantum/template/avr/config.h
index 7e4a01449..88402fbdd 100644
--- a/quantum/template/avr/config.h
+++ b/quantum/template/avr/config.h
@@ -192,10 +192,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 //#define NO_ACTION_ONESHOT
 
 /* disable these deprecated features by default */
-#ifndef LINK_TIME_OPTIMIZATION_ENABLE
-  #define NO_ACTION_MACRO
-  #define NO_ACTION_FUNCTION
-#endif
+#define NO_ACTION_MACRO
+#define NO_ACTION_FUNCTION
+
 /*
  * MIDI options
  */
diff --git a/quantum/template/ps2avrgb/config.h b/quantum/template/ps2avrgb/config.h
index 2eb484422..3f3fd5fd7 100644
--- a/quantum/template/ps2avrgb/config.h
+++ b/quantum/template/ps2avrgb/config.h
@@ -43,10 +43,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #define RGBLIGHT_ANIMATIONS
 
 /* disable these deprecated features by default */
-#ifndef LINK_TIME_OPTIMIZATION_ENABLE
-  #define NO_ACTION_MACRO
-  #define NO_ACTION_FUNCTION
-#endif
+#define NO_ACTION_MACRO
+#define NO_ACTION_FUNCTION
 
 /* key combination for magic key command */
 /* defined by default; to change, uncomment and set to the combination you want */
diff --git a/tmk_core/common.mk b/tmk_core/common.mk
index 4d4272d26..3d0b83a01 100644
--- a/tmk_core/common.mk
+++ b/tmk_core/common.mk
@@ -162,8 +162,6 @@ ifeq ($(strip $(LINK_TIME_OPTIMIZATION_ENABLE)), yes)
     endif
     EXTRAFLAGS += -flto
     TMK_COMMON_DEFS += -DLINK_TIME_OPTIMIZATION_ENABLE
-    TMK_COMMON_DEFS += -DNO_ACTION_MACRO
-    TMK_COMMON_DEFS += -DNO_ACTION_FUNCTION
 endif
 
 # Search Path
diff --git a/tmk_core/common/action.h b/tmk_core/common/action.h
index dd22023f9..c82c9c81b 100644
--- a/tmk_core/common/action.h
+++ b/tmk_core/common/action.h
@@ -28,6 +28,16 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 extern "C" {
 #endif
 
+/* Disable macro and function features when LTO is enabled, since they break */
+#ifdef LINK_TIME_OPTIMIZATION_ENABLE
+#    ifndef NO_ACTION_MACRO
+#        define NO_ACTION_MACRO
+#    endif
+#    ifndef NO_ACTION_FUNCTION
+#        define NO_ACTION_FUNCTION
+#    endif
+#endif
+
 /* tapping count and state */
 typedef struct {
     bool    interrupted : 1;