avutil/float_dsp-test: Add include config.h for HAVE_*

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/float_dsp-test.c

@@ -16,6 +16,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include "config.h"
+
 #include <float.h>
 #include <math.h>
 #include <stdint.h>