Option: uae_z3mem_start

Default: 0x10000000
Type: integer

p->z3autoconfig_start = 0x10000000;

Note sure if/when this option is used, nowadays. It looks like it is more
or less ignored / overwritten in mman.cpp.

See: [uae_z3mem_size], [uae_z3mem2_size], [uae_z3mapping]
See: [uae_force_0x10000000_z3]