[gnome-photos/sam/tracker3: 25/27] Fix build failure due to undefined M_PI constant

[Sam Thursfield <sthursfield src gnome org>]

commit f39a85bb1a82093f4ba615494ff7e95609674fc2
Author: Sam Thursfield <sam afuera me uk>
Date:   Wed May 27 13:07:58 2020 +0200

    Fix build failure due to undefined M_PI constant
    
    The <math.h> header needs to be included.
    
    Previously I suppose libtracker-sparql.h pulled this in.

 src/photos-utils.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/photos-utils.c b/src/photos-utils.c
index 1d7be577..d659b47d 100644
--- a/src/photos-utils.c
+++ b/src/photos-utils.c
@@ -32,6 +32,7 @@
 #include <glib.h>
 #include <tracker-sparql.h>
 #include <libgd/gd.h>
+#include <math.h>
 
 #include "photos-application.h"
 #include "photos-device-item.h"