system_get_version - get version string for system
#include <magenta/syscalls.h>
mx_status_t mx_system_get_version(char version[], uint32_t version_len);
system_get_version() fills in the given character array with a string identifying the version of the Magenta system currently running. The provided length must be large enough for the complete string including its null terminator.
system_get_version() returns MX_OK on success.
MX_ERR_BUFFER_TOO_SMALL version_len is too short.