save a bit space

config.h

@@ -16,12 +16,25 @@
 
 #pragma once
 
+// not more than 8 layers
+#define LAYER_STATE_8BIT
+
 // ensure home row modifiers don't cause havoc
 #define IGNORE_MOD_TAP_INTERRUPT
 
 // normal startup sound
 #define STARTUP_SONG SONG(PLANCK_SOUND)
 
+// no music mode used
+#define NO_MUSIC_MODE
+
+// we don't need locking
+#undef LOCKING_SUPPORT_ENABLE
+#undef LOCKING_RESYNC_ENABLE
+
+// we don't use one shot keys
+#define NO_ACTION_ONESHOT
+
 // no lights if we sleep
 #define RGBLIGHT_SLEEP
 

rules.mk

@@ -1,3 +1,14 @@
+# properly optimize
+LTO_ENABLE = yes
+
 # less debugging features
 COMMAND_ENABLE = no
 CONSOLE_ENABLE = no
+
+# we have some real mouse
+MOUSEKEY_ENABLE = no
+
+# more features we not use
+SPACE_CADET_ENABLE = no
+GRAVE_ESC_ENABLE = no
+MUSIC_ENABLE = no