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()) {
tem/linux-initrd.scm?id=3dd2ad6aeee91c98d0aba11ae37a4d0279fcae79&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-10-13 01:20:19 +0200'>2021-10-13</span></td><td><a href='/guix/commit/gnu/system/linux-initrd.scm?id=ec46a5338d60eb6714a47b67e0d1e92079412d73'>linux-initrd: Support checking NTFS volumes on boot.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/linux-initrd.scm (file-system-packages): Add ntfsfix/static
when needed.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-09-23 18:17:17 +0200'>2021-09-23</span></td><td><a href='/guix/commit/gnu/system/linux-initrd.scm?id=cd19c920b7bf15af6b8ea06aa5021487d65773a6'>linux-initrd: Support XFS.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/linux-initrd.scm (file-system-packages):
Add xfs_repair/static when needed.
(file-system-type-modules): Add ‘xfs’ module when needed.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-09-23 18:17:16 +0200'>2021-09-23</span></td><td><a href='/guix/commit/gnu/system/linux-initrd.scm?id=15489291d93bcd67e30eed686da0d58050ce1c0e'>linux-initrd: Include only the single ‘bcachefs’ binary.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/system/linux-initrd.scm (file-system-packages): Substitute
bcachefs/static for bcachefs-tools/static.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-09-23 18:17:16 +0200'>2021-09-23</span></td><td><a href='/guix/commit/gnu/system/linux-initrd.scm?id=68b219b9f482f09e7c55aaee4b64222d8c86172a'>gnu: Don't abuse check-btrfs-file-system to scan.</a><span class='msg-avail'>...<span class='msg-tooltip'>It was never guaranteed to be run for non-root file systems.  It was for
root file systems only due to a bug now fixed.

* gnu/build/file-systems.scm (check-btrfs-file-system): Don't invoke
‘btrfs device scan’ here.
* gnu/system/linux-initrd.scm (raw-initrd): Do so here if any btrfs file
systems are present.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2021-07-08 09:39:05 +0300'>2021-07-08</span></td><td><a href='/guix/commit/gnu/system/linux-initrd.scm?id=49e2e75ced01a821c84eb776cf42a36664eaa834'>gnu: %guile-3.0-static-stripped: Rename to %guile-static-stripped.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/make-bootstrap.scm (%guile-3.0-static-stripped): Rename
to %guile-static-stripped.
(%guile-bootstrap-tarball): Adjust accordingly.
* gnu/system/linux-initrd.scm (expression-&gt;initrd): Use
%guile-static-stripped as default guile.
* doc/guix.texi (initial RAM disk)[expression-&gt;initrd]: Adjust
documentation accordingly.
</span></span></td><td>Efraim Flashner</td></tr>