diff --git a/src/calibre/headless/headless_integration.cpp b/src/calibre/headless/headless_integration.cpp
index e87bf2c4ca..77b6ab0503 100644
--- a/src/calibre/headless/headless_integration.cpp
+++ b/src/calibre/headless/headless_integration.cpp
@@ -127,12 +127,10 @@ HeadlessIntegration *HeadlessIntegration::instance()
     return static_cast<HeadlessIntegration *>(QGuiApplicationPrivate::platformIntegration());
 }
 
-static QString themeName() { return QStringLiteral("headless"); }
 
-QStringList HeadlessIntegration::themeNames() const
-{
-    return QStringList(themeName());
-}
+#define THEME_NAME "headless"
+
+QStringList HeadlessIntegration::themeNames() const { return QStringList(THEME_NAME); }
 
 // Restrict the styles to "fusion" to prevent native styles requiring native
 // window handles (eg Windows Vista style) from being used.
@@ -155,7 +153,7 @@ public:
 
 QPlatformTheme *HeadlessIntegration::createPlatformTheme(const QString &name) const
 {
-    return name == themeName() ? new HeadlessTheme() : nullptr;
+    return name == THEME_NAME ? new HeadlessTheme() : nullptr;
 }
 
 QT_END_NAMESPACE