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()) {
82c621'>patches</a>/<a href='/guix/log/gnu/packages/patches/u-boot-riscv64-fix-extlinux.patch?id=2bd84c50ff7a8dafe83b6aa89cd0f01d5282c621'>u-boot-riscv64-fix-extlinux.patch</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/patches/u-boot-riscv64-fix-extlinux.patch?id=2bd84c50ff7a8dafe83b6aa89cd0f01d5282c621&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-07-09 17:22:18 -0700'>2020-07-09</span></td><td><a href='/guix/commit/gnu/packages/patches/u-boot-riscv64-fix-extlinux.patch?id=bce3c9748b4ba47cdb915492e5c7baaf3d3a2511'>gnu: u-boot: Update to 2020.07.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/bootloaders (u-boot): Update to 2020.07.
  (u-boot-pinebook-pro-rk3399): Remove patches.
* gnu/packages/patches:
  u-boot-DT-for-Pinebook-Pro.patch, u-boot-add-boe-nv140fhmn49-display.patch,
  u-boot-gpio-keys-binding-cons.patch, u-boot-leds-common-binding-con.patch,
  u-boot-support-Pinebook-Pro-laptop.patch,
  u-boot-video-rockchip-fix-build.patch: Remove patches.
  u-boot-riscv64-fix-extlinux.patch: Refresh patch.
* gnu/local.mk (dist_patch_DATA): Update accordingly.
</span></span></td><td>Vagrant Cascadian</td></tr>