diff --git a/makepanda/makepanda.py b/makepanda/makepanda.py
index 5e3c1b42fd..85f6282af7 100755
--- a/makepanda/makepanda.py
+++ b/makepanda/makepanda.py
@@ -1545,10 +1545,10 @@ def WriteConfigSettings():
 
     if (RUNTIME):
         dtool_config["HAVE_P3D_PLUGIN"] = '1'
-    
+
     # Whether it's present on the system doesn't matter here,
     # as the runtime itself doesn't include or link with X11.
-    if (RUNTIME and sys.platform.startswith("linux")):
+    if (RUNTIME and sys.platform != "darwin" and not sys.platform.startswith("win")):
         dtool_config["HAVE_X11"] = '1'
 
     if ("GENERIC_DXERR_LIBRARY" in SDK):