Merge branch 'rondom-do-https-request-header-cb' into 'master'

http: Allow passing header_cb to do_https_request

See merge request openconnect/openconnect!201

diff --cc array.c
Simple merge

diff --cc auth-globalprotect.c
Simple merge

diff --cc auth.c
Simple merge

diff --cc f5.c
Simple merge

diff --cc fortinet.c
Simple merge

diff --cc gpst.c
Simple merge

diff --cc oncp.c
Simple merge

diff --cc openconnect-internal.h
Simple merge