In function 'process_record_user':
keyboards/ploopyco/trackball/keymaps/devmed/keymap.c:63:17: error: 'is_drag_scroll' undeclared (first use in this function)
                 is_drag_scroll ^= 1;
                 ^~~~~~~~~~~~~~
keyboards/ploopyco/trackball/keymaps/devmed/keymap.c:63:17: note: each undeclared identifier is reported only once for each function it appears in
 [ERRORS]
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make[1]: *** [.build/obj_ploopyco_trackball_rev1_005_devmed/keyboards/ploopyco/trackball/keymaps/devmed/keymap.o] Error 1
make: *** [ploopyco/trackball/rev1_005:devmed] Error 1