commit 21f7280ad3cff8362c770cce02d932dce29dc1d6
Author: Thorsten Wißmann <edu@thorsten-wissmann.de>
Date:   Fri Apr 10 09:16:45 2020 +0200

    Use %zu in printf to print size_t variable (#735)

diff --git a/src/ewmh.cpp b/src/ewmh.cpp
index 0fe9cbc9..51497b32 100644
--- a/src/ewmh.cpp
+++ b/src/ewmh.cpp
@@ -143,7 +143,7 @@ long Ewmh::windowGetInitialDesktop(Window win)
 
 void Ewmh::InitialState::print(FILE *file)
 {
-    fprintf(file, "EWMH: %lu desktops:", numberOfDesktops);
+    fprintf(file, "EWMH: %zu desktops:", numberOfDesktops);
     for (const auto& n : desktopNames) {
         fprintf(file, " \'%s\'", n.c_str());
     }
