Expose low-level opendir/readdir dir traversal.

* stream.c (UTF_DECL_OPENDIR): Macro defined, to enable
w_opendir declaration in utf8.h.
(w_opendir): Static function removed.

* sysif.c (UTF_DECL_OPENDIR): Macro defined.
(dir_s): Symbol defined unconditionally now, regardless of
HAVE_PWUID.
(dirent_s): New symbol.
(dirent_st): New static variable.
(struct dir): New struct type.
(opendir_free, opendir_mark opendir_wrap, readdir_wrap): New
static functions.
(opendir_ops): New static structure.
(sysif_init): Intern dirent symbol. Create dirent structure
type. Register opendir and readdir intrinsic functions.
Register variables dt-blk, dt-chr, dt-dir, dt-fifo, dt-lnk,
dt-reg, dt-sock and dt-unknown.

* utf8.c (UTF8_DECL_OPENDIR): Macro defined.
(w_opendir): Function moved here from stream.c, and turned
external.

* utf8.h (w_opendir): Declared, conditionally on
UTF8_DECL_OPENDIR being defined, so that most modules that
include utf8.h don't have to include <dirent.h>.

* txr.1: Documented.

diff --git a/sysif.c b/sysif.c

1 files changed, 1 insertions, 9 deletions

diff --git a/stream.c b/stream.c
index d9bd7992..bd22a5e5 100644
--- a/stream.c
+++ b/stream.c
@@ -25,6 +25,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#define UTF8_DECL_OPENDIR
 #include <stdio.h>
 #include <string.h>
 #include <stddef.h>
@@ -4052,15 +4053,6 @@ val get_string(val stream_in, val nchars, val close_after_p)
   return get_string_from_stream(strstream);
 }
 
-static DIR *w_opendir(const wchar_t *wname)
-{
-  char *name = utf8_dup_to(wname);
-  DIR *d = opendir(name);
-  free(name);
-  return d;
-}
-
-
 val open_directory(val path)
 {
   DIR *d = w_opendir(c_str(path));