Index: plugins/platforms/x11/standalone/glxbackend.cpp
===================================================================
--- plugins/platforms/x11/standalone/glxbackend.cpp
+++ plugins/platforms/x11/standalone/glxbackend.cpp
@@ -509,7 +509,7 @@
     return m_visualDepthHash.value(visual);
 }
 
-static inline int bitCount(uint32_t mask)
+static inline constexpr int bitCount(uint32_t mask)
 {
 #if defined(__GNUC__)
     return __builtin_popcount(mask);