[gtk] gdk/win32/gdkdrag-win32.c: Include math.h

[Chun-wei Fan <fanchunwei src gnome org>]

commit 4784c5a9808f97fd43e67edb33d65b02109b9e02
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Fri Mar 29 16:48:29 2019 +0800

    gdk/win32/gdkdrag-win32.c: Include math.h
    
    We need that for round().

 gdk/win32/gdkdrag-win32.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gdk/win32/gdkdrag-win32.c b/gdk/win32/gdkdrag-win32.c
index 25723451e2..318013c2d9 100644
--- a/gdk/win32/gdkdrag-win32.c
+++ b/gdk/win32/gdkdrag-win32.c
@@ -29,6 +29,7 @@
 
 #include <io.h>
 #include <fcntl.h>
+#include <math.h>
 
 /*
  * Support for OLE-2 drag and drop added at Archaeopteryx Software, 2001