stdbool.h (along with float.h, limits.h, stdarg.h, stddef.h, stdint.h, and some other library facilities) is required to be provided even in freestanding environment so, at least as long as you use an ISO C conformant compiler, you can always include those even if you don’t have a libc implementation
If you’re 3 thousand kilometers away from it I’d make it into a headless machine by unplugging the internal display and getting a kvm for it. Or just make sure you have contact with someone who can type in commands for you when anything goes really sideways