Extract LINUX_VERSION_CODE from running kernel via vDSO.
Extract LINUX_VERSION_CODE from running kernel via vDSO.

This method reuses a stable interface provided for glibc, avoids runtime
header file parsing or regexes, and the vDSO structure should remain
stable over time. Fall back to the compile time constant if search
fails.

iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace