Baby steps. This permits building without much of gvisor, but not all of it.
Updates #17283
Change-Id: I8433146e259918cc901fe86b4ea29be22075b32c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This only saves ~32KB in the minimal linux/amd64 binary, but it's a
step towards permitting not depending on gvisor for small builds.
Updates #17283
Change-Id: Iae8da5e9465127de354dbcaf25e794a6832d891b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>