Initial support for MacOS.

This will soon be complemented with MacOS specific source code files and
INSTALL.MacOS.

I (Andy) have decided to get rid of a number of #include <sys/types.h>.
I've verified it's ok (both by examining /usr/include/*.h and compiling)
on a number of Unix platforms. Unfortunately I don't have Windows box
to verify this on. I really appreciate if somebody could try to compile
it and contact me a.s.a.p. in case a problem occurs.

Submitted by: Roy Wood <roy@centricsystems.ca>
Reviewed by: Andy Polyakov <appro@fy.chalmers.se>

ssl/ssl_cert.c

diff --git a/ssl/ssl_cert.c b/ssl/ssl_cert.c
index 6d2511f..a695d04 100644
--- a/ssl/ssl_cert.c
+++ b/ssl/ssl_cert.c
@@ -105,14 +105,22 @@
  */
 
 #include <stdio.h>
-#include <sys/types.h>
-#if !defined(WIN32) && !defined(VSM) && !defined(NeXT)
+
+#include "openssl/e_os.h"
+
+#ifndef NO_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#if !defined(WIN32) && !defined(VSM) && !defined(NeXT) && !defined(MAC_OS_pre_X)
 #include <dirent.h>
 #endif
+
 #ifdef NeXT
 #include <sys/dir.h>
 #define dirent direct
 #endif
+
 #include <openssl/objects.h>
 #include <openssl/bio.h>
 #include <openssl/pem.h>
@@ -671,6 +679,7 @@
 
 #ifndef WIN32
 #ifndef VMS			/* XXXX This may be fixed in the future */
+#ifndef MAC_OS_pre_X
 
 int SSL_add_dir_cert_subjects_to_stack(STACK_OF(X509_NAME) *stack,
 				       const char *dir)
@@ -714,3 +723,4 @@
 
 #endif
 #endif
+#endif