Merge pull request #3393 from chungy/freebsd-fixes

Add some defines to build succesfully on FreeBSD

src/include/86box/plat_dir.h

@@ -66,6 +66,9 @@ extern void           seekdir(DIR *, long);
 extern int            closedir(DIR *);
 
 #    define rewinddir(dirp) seekdir(dirp, 0L)
+#elif defined(__FreeBSD__)
+/* FreeBSD uses dirent.h instead of sys/dir.h */
+#    include <dirent.h>
 #else
 /* On linux and macOS, use the standard functions and types */
 #    include <sys/dir.h>