avutil/internal: Move libm inclusion to the beginning

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/internal.h

@@ -40,6 +40,7 @@
 #include <stdio.h>
 #include "config.h"
 #include "attributes.h"
+#include "libm.h"
 #include "macros.h"
 #include "pixfmt.h"
 
@@ -86,8 +87,6 @@
  */
 #define FF_FIELD_AT(type, off, obj) (*(type *)((char *)&(obj) + (off)))
 
-#include "libm.h"
-
 /**
  * Return NULL if CONFIG_SMALL is true, otherwise the argument
  * without modification. Used to disable the definition of strings.