[gtk+/gtk-2-24] msw_style.c: Use G_PI rather than M_PI

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

commit 278325f611020cba8347d0f2e169630eef3aedb5
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Tue Nov 8 12:37:15 2011 +0800

    msw_style.c: Use G_PI rather than M_PI
    
    M_PI is not universally available...

 modules/engines/ms-windows/msw_style.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/modules/engines/ms-windows/msw_style.c b/modules/engines/ms-windows/msw_style.c
index 9be99aa..ba3a60b 100755
--- a/modules/engines/ms-windows/msw_style.c
+++ b/modules/engines/ms-windows/msw_style.c
@@ -2620,7 +2620,7 @@ draw_themed_tab_button (GtkStyle *style,
                   draw_rect.y + draw_rect.height * 0.5);
 
   if (gap_side == GTK_POS_LEFT || gap_side == GTK_POS_RIGHT) {
-    cairo_rotate (cr, M_PI/2.0);
+    cairo_rotate (cr, G_PI/2.0);
   }
 
   if (gap_side == GTK_POS_LEFT || gap_side == GTK_POS_BOTTOM) {