Don't use local_fgets on sockets; ftell doesn't work on sockets.

(Thanks to Jorgen "forcer" Schaefer.)
* ports.h (SCM_NOFTELL): New flag.
* fports.c (local_fgets): If it's set, use the generic fgets.
* socket.c (scm_socket): Set SCM_NOFTELL on the ports we produce.

libguile/fports.c

@@ -416,6 +416,16 @@ local_fgets (SCM port, int *len)
 
   pre_read (port);
 
+  /* If this is a socket port or something where we can't rely on
+     ftell to determine how much we've read, then call the generic
+     function.  We could use a separate scm_ptobfuns table with
+     scm_generic_fgets, but then we'd have to change SCM_FPORTP, etc.
+     Ideally, it should become something that means "this port has a
+     file descriptor"; sometimes we reject sockets when we shouldn't.
+     But I'm too stupid at the moment to do that right.  */
+  if (SCM_CAR (port) & SCM_NOFTELL)
+    return scm_generic_fgets (port, len);
+
   f = (FILE *) SCM_STREAM (port);
   if (feof (f))
     return NULL;

libguile/ports.h

@@ -83,6 +83,7 @@ extern int scm_port_table_size; /* Number of ports in scm_port_table.  */
 #define SCM_RDNG	(2L<<16) /* Is it a readable port? */
 #define SCM_WRTNG	(4L<<16) /* Is it writable? */
 #define SCM_BUF0	(8L<<16)
+#define SCM_NOFTELL     (16L<<16) /* Does ftell work on this?  Yuck!  */
 #define SCM_CRDY	(32L<<16) /* Should char-ready? return #t? */
 
 /* A mask used to clear the char-ready port flag. */

libguile/socket.c

@@ -107,6 +107,7 @@ scm_socket (family, style, proto)
   SCM_DEFER_INTS;
   fd = socket (SCM_INUM (family), SCM_INUM (style), SCM_INUM (proto));
   result = scm_sock_fd_to_port (fd, s_socket);
+  SCM_SETOR_CAR (result, SCM_NOFTELL);
   SCM_ALLOW_INTS;
   return result;
 }