avutil/color_utils: Mark test_data as static const

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

libavutil/color_utils.c

@@ -224,7 +224,7 @@ avpriv_trc_function avpriv_get_trc_function_from_trc(enum AVColorTransferCharact
 int main(int argc, char *argv[])
 {
   int i, j;
-  double test_data[] = {
+  static const double test_data[] = {
       -0.1, -0.018053968510807, -0.01, -0.00449, 0.0, 0.00316227760, 0.005,
       0.009, 0.015, 0.1, 1.0, 52.37, 125.098765, 1999.11123, 6945.443,
       15123.4567, 19845.88923, 98678.4231, 99999.899998