MINOR: htx: Use a macro for overhead induced by HTX

The overhead induced by the HTX format was set to the HTX structure itself
and two HTX blocks. It was set this way to optimize zero-copy during
transfers. This value may (and will) be used at different places. Thus we
now use a macro, called HTX_BUF_OVERHEAD.

(cherry picked from commit 7393bf7e424d4cd2e0927bf4dc95eb799ec67dd4)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit bffaf79459dae517a212f3f84269251d689491fd)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit bfb0e2a53611433b17400c1d2b318334a57255b9)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit cdd881f788ed404c45ec89f1a01dda0b4cccbbd3)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
2 files changed