buildroot

libwebsockets: cherry-pick upstream patch for v2.1.1

This commit cherry-picks an upstream patch that fixes a compile error
that was introduced in v2.1.1

Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
(cherry picked from commit f80fc852a3f9fc26fe522cf843b075da52c68dbc)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>