unix: djgpp errno.h have no ENOTSUP, so define it to Linux value.

pohmelie · pfalcon · commit cee888255bc0 · 2016-04-03T23:23:01.000+03:00
diff --git a/unix/mpconfigport_freedos.h b/unix/mpconfigport_freedos.h
@@ -36,3 +36,9 @@
 
 // djgpp dirent struct does not have d_ino field
 #undef _DIRENT_HAVE_D_INO
+
+// djgpp errno.h have no ENOTSUP
+#include <errno.h>
+#ifndef ENOTSUP
+#define ENOTSUP 88
+#endif
