This is based on the respectve patch from NixPkgs, but with the parts pinning
mysql and postgresql executables removed. See our package definition on why.

diff --git a/src/akonadicontrol/agentmanager.cpp b/src/akonadicontrol/agentmanager.cpp
--- a/src/akonadicontrol/agentmanager.cpp
+++ b/src/akonadicontrol/agentmanager.cpp
@@ -47,7 +47,7 @@ public:
         connect(this, &Akonadi::ProcessControl::unableToStart, this, []() {
             QCoreApplication::instance()->exit(255);
         });
-        start(QStringLiteral("akonadiserver"), args, RestartOnCrash);
+        start(QStringLiteral(NIX_OUT "/bin/akonadiserver"), args, RestartOnCrash);
     }

     ~StorageProcessControl() override
@@ -69,7 +69,7 @@ public:
         connect(this, &Akonadi::ProcessControl::unableToStart, this, []() {
             qCCritical(AKONADICONTROL_LOG) << "Failed to start AgentServer!";
         });
-        start(QStringLiteral("akonadi_agent_server"), args, RestartOnCrash);
+        start(QStringLiteral(NIX_OUT "/bin/akonadi_agent_server"), args, RestartOnCrash);
     }

     ~AgentServerProcessControl() override
diff --git a/src/akonadicontrol/agentprocessinstance.cpp b/src/akonadicontrol/agentprocessinstance.cpp
--- a/src/akonadicontrol/agentprocessinstance.cpp
+++ b/src/akonadicontrol/agentprocessinstance.cpp
@@ -62,7 +62,7 @@ bool AgentProcessInstance::start(const AgentType &agentInfo)
     } else {
         Q_ASSERT(agentInfo.launchMethod == AgentType::Launcher);
         const QStringList arguments = QStringList() << executable << identifier();
-        const QString agentLauncherExec = Akonadi::StandardDirs::findExecutable(QStringLiteral("akonadi_agent_launcher"));
+        const QString agentLauncherExec = QLatin1String(NIX_OUT "/bin/akonadi_agent_launcher");
         mController->start(agentLauncherExec, arguments);
     }
     return true;
diff --git a/src/server/storage/dbconfigmysql.cpp b/src/server/storage/dbconfigmysql.cpp
--- a/src/server/storage/dbconfigmysql.cpp
+++ b/src/server/storage/dbconfigmysql.cpp
@@ -215,7 +215,7 @@ bool DbConfigMysql::startInternalServer()
 #endif

     // generate config file
-    const QString globalConfig = StandardDirs::locateResourceFile("config", QStringLiteral("mysql-global.conf"));
+    const QString globalConfig = QLatin1String(NIX_OUT "/etc/xdg/akonadi/mysql-global.conf");
     const QString localConfig = StandardDirs::locateResourceFile("config", QStringLiteral("mysql-local.conf"));
     const QString actualConfig = StandardDirs::saveDir("data") + QLatin1String("/mysql.conf");
     if (globalConfig.isEmpty()) {
th><th class='left'>Author</th></tr>
<tr><td><span title='2021-06-23 23:35:27 +0200'>2021-06-23</span></td><td><a href='/guix/commit/build-aux/compile-all.scm?id=ef82ba9dd94369926eb13325d5e7da4306d23dd7'>build: Makefile splits Scheme compilation in four steps.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/48963&gt;.
Reported by Julien Lepiller &lt;julien@lepiller.eu&gt;.

This reduces peak memory consumption to something less unreasonable.

* Makefile.am (make-go): Depend on 'make-*-go' targets; remove body.
(guile-compilation-rule): New function.
(MODULES_CORE, MODULES_PACKAGES, MODULES_SYSTEM, MODULES_CLI): New
variables.
&lt;top level&gt;: Call 'guile-compilation-rule' 4 times.
* build-aux/compile-all.scm &lt;top level&gt;: Expect "--total" and
"--processed".  Take them into account when displaying progress
reports.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-06-18 14:18:06 +0200'>2021-06-18</span></td><td><a href='/guix/commit/build-aux/compile-all.scm?id=003728cfab907be5df1411c5faaf466a2b8d5ba2'>build: Remove Guile 2.2 workaround.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/compile-all.scm &lt;top level&gt;: Remove Guile 2.2 workaround.
</span></span></td><td>Ludovic Courtès</td></tr>