dct/fft-test: use a replacement getopt() if the system has none present.

This allows compiling and running these tests on systems lacking a built-
in version of getopt(), such as MSVC.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/dct-test.c

@@ -25,10 +25,13 @@
  * Started from sample code by Juan J. Sierralta P.
  */
 
+#include "config.h"
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#if HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <math.h>
 
 #include "libavutil/cpu.h"
@@ -474,6 +477,10 @@ static void help(void)
            "-t          speed test\n");
 }
 
+#if !HAVE_GETOPT
+#include "compat/getopt.c"
+#endif
+
 int main(int argc, char **argv)
 {
     int test_idct = 0, test_248_dct = 0;