Undefined reference when linking against libhiredis using the libev adapter

[Dan Parnham]

When linking an application that uses libhiredis with the libev adapter on Ubuntu 20.04 it fails with
/usr/include/hiredis/adapters/libev.h:122: undefined reference to `hi_malloc(unsigned long)'

This was reported to the hiredis project back in February and has since been patched
https://github.com/redis/hiredis/issues/769

but the version available in the Ubuntu 20.04 repositories (libhiredis-dev 0.14.0-6) is from before it was fixed.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: libhiredis0.14 0.14.0-6
ProcVersionSignature: Ubuntu 5.4.0-40.44-generic 5.4.44
Uname: Linux 5.4.0-40-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.4
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Jul 17 22:58:16 2020
InstallationDate: Installed on 2020-07-15 (2 days ago)
InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: hiredis
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dan Parnham (teadriven)]

Two years on and this is still breaking our automated package builds for focal (bionic and jammy are both fine).

+broca *failed* | /usr/bin/ld: obj/native/default/broca/Manager.o: in function `redisLibevAttach(ev_loop*, redisAsyncContext*)':
+broca *failed* | /usr/include/hiredis/adapters/libev.h:122: undefined reference to `hi_malloc(unsigned long)'