diff --git a/src/Magnum/DebugMessage.cpp b/src/Magnum/DebugMessage.cpp
index 7be007f5c..fd3a690e4 100644
--- a/src/Magnum/DebugMessage.cpp
+++ b/src/Magnum/DebugMessage.cpp
@@ -38,10 +38,11 @@ namespace {
 
 /** @todo Re-enable when extension wrangler is available for ES */
 #ifndef MAGNUM_TARGET_GLES
+void
 #ifdef CORRADE_TARGET_WINDOWS
 APIENTRY
 #endif
-void callbackWrapper(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam) {
+callbackWrapper(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam) {
     Context::current()->state().debug->messageCallback(DebugMessage::Source(source), DebugMessage::Type(type), id, DebugMessage::Severity(severity), std::string(message, length), userParam);
 }
 #endif