On 10.4.12, a new typedef has been introduced on InnoDB:
storage/innobase/include/rem0types.h:34: typedef short unsigned int offset_t
This typedef conflicts with an AIX typdef
/usr/include/sys/types.h:716: typedef long long int offset_t
It seems a mass substitution of ulint type to offset_t was made between mariadb10.4.11 and 10.4.12.