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/fft-test.c

@@ -34,7 +34,9 @@
 #include "rdft.h"
 #endif
 #include <math.h>
+#if HAVE_UNISTD_H
 #include <unistd.h>
+#endif
 #include <stdlib.h>
 #include <string.h>
 
@@ -229,6 +231,10 @@ enum tf_transform {
     TRANSFORM_DCT,
 };
 
+#if !HAVE_GETOPT
+#include "compat/getopt.c"
+#endif
+
 int main(int argc, char **argv)
 {
     FFTComplex *tab, *tab1, *tab_ref;