Update '?=' references in rules.mk. Add support for ortho_4x12 layout.

keyboards/meira/meira.h

@@ -38,3 +38,5 @@ void reset_keyboard_kb(void);
 }
 
 #endif
+
+#define LAYOUT_ortho_4x12 KEYMAP

keyboards/meira/rules.mk

@@ -53,24 +53,24 @@ OPT_DEFS += -DBOOTLOADER_SIZE=4096
 # Build Options
 #   change yes to no to disable
 #
-BOOTMAGIC_ENABLE ?= no      # Virtual DIP switch configuration(+1000)
-MOUSEKEY_ENABLE ?= yes       # Mouse keys(+4700)
-EXTRAKEY_ENABLE ?= yes       # Audio control and System control(+450)
-CONSOLE_ENABLE ?= yes        # Console for debug(+400)
-COMMAND_ENABLE ?= yes        # Commands for debug and configuration
+BOOTMAGIC_ENABLE = no      # Virtual DIP switch configuration(+1000)
+MOUSEKEY_ENABLE = yes       # Mouse keys(+4700)
+EXTRAKEY_ENABLE = yes       # Audio control and System control(+450)
+CONSOLE_ENABLE = yes        # Console for debug(+400)
+COMMAND_ENABLE = yes        # Commands for debug and configuration
 # Do not enable SLEEP_LED_ENABLE. it uses the same timer as BACKLIGHT_ENABLE
-SLEEP_LED_ENABLE ?= no       # Breathing sleep LED during USB suspend
+SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
 # if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
-NKRO_ENABLE ?= no            # USB Nkey Rollover
-BACKLIGHT_ENABLE ?= no       # Enable keyboard backlight functionality on B7 by default
-MIDI_ENABLE ?= no            # MIDI support (+2400 to 4200, depending on config)
-UNICODE_ENABLE ?= no         # Unicode
-BLUETOOTH_ENABLE ?= no       # Enable Bluetooth with the Adafruit EZ-Key HID
-AUDIO_ENABLE ?= no           # Audio output on port C6
-RGBLIGHT_ENABLE ?= no       # Enable WS2812 RGB underlight.  Do not enable this with audio at the same time.
-FAUXCLICKY_ENABLE ?= no      # Use buzzer to emulate clicky switches
+NKRO_ENABLE = no            # USB Nkey Rollover
+BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality on B7 by default
+MIDI_ENABLE = no            # MIDI support (+2400 to 4200, depending on config)
+UNICODE_ENABLE = no         # Unicode
+BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID
+AUDIO_ENABLE = no           # Audio output on port C6
+RGBLIGHT_ENABLE = no       # Enable WS2812 RGB underlight.  Do not enable this with audio at the same time.
+FAUXCLICKY_ENABLE = no      # Use buzzer to emulate clicky switches
 
-ISSI_ENABLE ?= no			# If the I2C pullup resistors aren't install this must be disabled
+ISSI_ENABLE = no			# If the I2C pullup resistors aren't install this must be disabled
 #WATCHDOG_ENABLE = yes		# Resets keyboard if matrix_scan isn't run every 250ms
 
 CUSTOM_MATRIX = yes
@@ -84,3 +84,4 @@ ifeq ($(strip $(WATCHDOG_ENABLE)), yes)
 endif
 
 DEFAULT_FOLDER = meira/promicro
+LAYOUTS = ortho_4x12