$ make ymd96:default
Making ymd96 with keymap default

avr-gcc.exe (AVR_8_bit_GNU_Toolchain_3.5.4_1709) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Size before:
   text    data     bss     dec     hex filename
      0   26828       0   26828    68cc ./.build/ymd96_default.hex

Compiling: keyboards/ymd96/matrix.c                                                                 [OK]
Compiling: keyboards/ymd96/i2c.c                                                                    [OK]
Compiling: keyboards/ymd96/ymd96.c                                                                  [OK]
Compiling: keyboards/ymd96/keymaps/default/keymap.c                                                keyboards/ymd96/keymaps/default/keymap.c:46:5: error: implicit declaration of function 'TD' [-Werror=implicit-function-declaration]
     [_DEFLT] = KEYMAP(
     ^
keyboards/ymd96/keymaps/default/keymap.c:46:5: error: initializer element is not constant
keyboards/ymd96/keymaps/default/keymap.c:46:5: error: (near initialization for 'keymaps[0][5][2]')
keyboards/ymd96/keymaps/default/keymap.c:46:5: error: initializer element is not constant
keyboards/ymd96/keymaps/default/keymap.c:46:5: error: (near initialization for 'keymaps[0][5][3]')
keyboards/ymd96/keymaps/default/keymap.c:74:1: error: unknown type name 'qk_tap_dance_action_t'
 qk_tap_dance_action_t tap_dance_actions[] = {
 ^
keyboards/ymd96/keymaps/default/keymap.c:75:3: error: implicit declaration of function 'ACTION_TAP_DANCE_DOUBLE' [-Werror=implicit-function-declaration]
   [TD_F1] = ACTION_TAP_DANCE_DOUBLE(KC_1, KC_F1),
   ^
keyboards/ymd96/keymaps/default/keymap.c:75:3: error: initializer element is not constant
keyboards/ymd96/keymaps/default/keymap.c:75:3: error: (near initialization for 'tap_dance_actions[0]')
keyboards/ymd96/keymaps/default/keymap.c:76:3: error: initializer element is not constant
   [TD_F2] = ACTION_TAP_DANCE_DOUBLE(KC_2, KC_F2),
   ^
keyboards/ymd96/keymaps/default/keymap.c:76:3: error: (near initialization for 'tap_dance_actions[1]')
cc1.exe: all warnings being treated as errors
 [ERRORS]
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make[1]: *** [tmk_core/rules.mk:360: .build/obj_ymd96_default/keyboards/ymd96/keymaps/default/keymap.o] Error 1
Make finished with errors
make: *** [Makefile:543: ymd96:default] Error 1