Merge branch 'less_unstable_use' into 'master'

src/acpi/hpet.rs

src/acpi/madt.rs

src/arch/aarch64/device/gic.rs

src/arch/aarch64/device/rtc.rs

src/arch/aarch64/rmm.rs

src/arch/aarch64/stop.rs

src/arch/x86/device/local_apic.rs

src/arch/x86/rmm.rs

src/arch/x86/stop.rs

src/arch/x86_64/device/local_apic.rs

src/arch/x86_64/stop.rs

src/context/memory.rs

src/context/switch.rs

src/lib.rs

src/scheme/proc.rs

src/scheme/user.rs

src/syscall/fs.rs

src/syscall/futex.rs