CMakePM: Expand ${hostSystemName} for build presets

Fixes: QTCREATORBUG-28935
Change-Id: Ie645d80a9743108e3760096b6829e881677e249b
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/cmakeprojectmanager/presetsmacros.cpp

@@ -61,6 +61,7 @@ static void expandAllButEnv(const PresetsDetails::BuildPreset &preset,
     value.replace("${sourceDirName}", sourceDirectory.fileName());
 
     value.replace("${presetName}", preset.name);
+    value.replace("${hostSystemName}", getHostSystemName(sourceDirectory.osType()));
     value.replace("${pathListSep}",
                   Utils::OsSpecificAspects::pathListSeparator(sourceDirectory.osType()));
 }