the_default_budget_follows_the_installed_memory_read compares the default
budget with the 1 GiB fallback when the installed memory can't be read,
as default_history_budget does, instead of failing. The reader itself is
still checked by vectorcraft-render's installed_memory_is_read.
The undo history line in docs/target-app-parity.md says the budget is at
most a quarter of the address space in a 32-bit build.
dotCooCoo
f3104b154c