swscale: #include "libavutil/mathematics.h"

this file uses the M_PI macro since
4e74187db2f5db52f88729efc662df9d6bc763e1, so include the correct header
directly.

Signed-off-by: Reinhard Tartler <siretart@tauware.de>

(cherry picked from commit 5089ce1b5a)

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
(cherry picked from commit 851098c9e0)

Conflicts:

	libswscale/utils.c

libswscale/utils.c

@@ -42,6 +42,7 @@
 #include "libavutil/x86_cpu.h"
 #include "libavutil/avutil.h"
 #include "libavutil/bswap.h"
+#include "libavutil/mathematics.h"
 #include "libavutil/pixdesc.h"
 
 unsigned swscale_version(void)