Function crash_context::crash_context_getcontext

pub unsafe extern "C" fn crash_context_getcontext(
    ctx: *mut ucontext_t
) -> i32

A portable implementation of getcontext since it is not supported by all libc implementations, namely musl, as it has been deprecated from POSIX for over a decade

The implementation is ported from Breakpad, which is itself ported from libunwind