runtime: add trivial mmap failure check

[mischief]

No description provided.

[github-actions]

Build for testing:
artifacts x86_64
artifacts i686
artifacts armhf
artifacts aarch64
Use at your own risk.

[github-actions]

Build for testing:
artifacts x86_64
artifacts i686
artifacts armhf
artifacts aarch64
Use at your own risk.

[TheAssassin]

Looks good, but in theory, you'd have to add additional checks for open, close etc.

[mischief]

Looks good, but in theory, you'd have to add additional checks for open, close etc.

i could if you wish, but i thought the mmap was a bit more hazardous since it will likely segfault on failure rather than just give an error when it fails due to the subsequent array access into the pointer.