diff --git a/src/gui_w32.c b/src/gui_w32.c
index 7bdbf41..f53318d 100644
--- a/src/gui_w32.c
+++ b/src/gui_w32.c
@@ -272,9 +272,11 @@
 # undef MSG
 typedef int MSG;
 typedef int NEWTEXTMETRIC;
+typedef int NMHDR;
 typedef int OSVERSIONINFO;
 typedef int PWORD;
 typedef int RECT;
+typedef int SIZE;
 typedef int UINT;
 typedef int WORD;
 typedef int WPARAM;