Why is LBER_SOCKET of type long instead of int?

The definition of LBER_SOCKET in lber.h:
#ifndef macintosh
#if defined( _WINDOWS ) || defined( _WIN32) || defined( _CONSOLE )
#include <winsock.h> /* for SOCKET */
typedef SOCKET LBER_SOCKET;
#else
typedef long LBER_SOCKET;
#endif /* _WINDOWS */
#else /* macintosh */
typedef void *LBER_SOCKET;
#endif /* macintosh */

(as an aside, what is a socket/file descriptor on mac?  Why a void *?)

This should correspond to the native socket/file descriptor type on the 
platform, and is used as such (lber-int.h):

struct sockbuf {
	LBER_SOCKET	sb_sd;
...
	LBER_SOCKET	sb_copyfd;	/* for LBER_SOCKBUF_OPT_TO_FILE* opts */
...

On every unix/linux platform, the native socket/file descriptor type is 
a 32bit int.  So, I propose we change LBER_SOCKET to int.

In addition, we don't use the type LBER_SOCKET consistently.  There are 
a number of places where we use the value of sb_sd such as the following 
(liblber/io.c):
		if ( sb->sb_ext_io_fns.lbextiofn_read != NULL ) {
			rc = sb->sb_ext_io_fns.lbextiofn_read(
			    sb->sb_sd, sb->sb_ber.ber_buf,
			    ((sb->sb_options & LBER_SOCKBUF_OPT_NO_READ_AHEAD)
			    && (len < READBUFSIZ)) ? len : READBUFSIZ,
			    sb->sb_ext_io_fns.lbextiofn_socket_arg );

However, the definition of sb->sb_ext_io_fns.lbextiofn_read() is this:
typedef int (LDAP_C LDAP_CALLBACK LDAP_X_EXTIOF_READ_CALLBACK)( int s,
	void *buf, int bufsize, struct lextiof_socket_private *socketarg );

The first argument should really be LBER_SOCKET s instead of int s.

Finally, there are a few places where we should use casts to make clear 
what is going on e.g. ldappr-public.c:
int LDAP_CALL
prldap_import_connection (LDAP *ld)
{
	int rc = LDAP_SUCCESS; /* optimistic */
	int shared = 1; /* Assume shared init */
	LBER_SOCKET orig_socket = -1;
	PRLDAPIOSessionArg *prsessp = NULL;
	PRLDAPIOSocketArg *prsockp = NULL;
	PRFileDesc *pr_socket = NULL;
...
	/* Retrieve TCP socket's integer file descriptor */
     	if ( ldap_get_option( ld, LDAP_OPT_DESC, &orig_socket ) < 0 ) {
...
	/* Import file descriptor of connection made via ldap_init() */
	if (NULL == (pr_socket = PR_ImportTCPSocket(orig_socket)) ) {
	    ldap_set_lderrno( ld, LDAP_LOCAL_ERROR, NULL, NULL );

The definition of PR_ImportTCPSocket() is this:
NSPR_API(PRFileDesc*)  PR_ImportTCPSocket(PRInt32 osfd);

I suppose we don't need the cast (PRInt32)orig_socket if we change 
LBER_SOCKET to int, but it is of a different type nonetheless.