MFH: r445240 r446176

Update to version 1.7.8.

Fix net/haproxy and net/haproxy-devel build on ARM

USE_REGPARM=1 is specific for amd64 and i386. Conditionalize its definition and
let the port build on ARM

Approved by: demon (maintainer)
Obtained from: pfSense
Sponsored by: Rubicon Communications, LLC (Netgate)
Differential Revision: https://reviews.freebsd.org/D11637
Approved by: ports-secteam (junovitch)