Get dirmod.c on the same page as port.h about whether we use pgsymlink

on Cygwin (answer: we don't).  Also try to unwind the #ifdef spaghetti
a little bit.  Untested but hopefully I didn't break anything.

src/include/port.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/port.h,v 1.111 2007/04/13 10:30:30 mha Exp $
+ * $PostgreSQL: pgsql/src/include/port.h,v 1.112 2007/07/12 23:28:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -241,8 +241,7 @@ extern int	pclose_check(FILE *stream);
 
 #if defined(WIN32) || defined(__CYGWIN__)
 /*
- *	Win32 doesn't have reliable rename/unlink during concurrent access,
- *	and we need special code to do symlinks.
+ *	Win32 doesn't have reliable rename/unlink during concurrent access.
  */
 extern int	pgrename(const char *from, const char *to);
 extern int	pgunlink(const char *path);
@@ -255,9 +254,14 @@ extern int	pgunlink(const char *path);
 #define rename(from, to)		pgrename(from, to)
 #define unlink(path)			pgunlink(path)
 
+#endif   /* defined(WIN32) || defined(__CYGWIN__) */
+
 /*
+ *	Win32 also doesn't have symlinks, but we can emulate them with
+ *	junction points on newer Win32 versions.
+ *
  *	Cygwin has its own symlinks which work on Win95/98/ME where
- *	junction points don't, so use it instead.  We have no way of
+ *	junction points don't, so use those instead.  We have no way of
  *	knowing what type of system Cygwin binaries will be run on.
  *		Note: Some CYGWIN includes might #define WIN32.
  */
@@ -266,7 +270,6 @@ extern int	pgsymlink(const char *oldpath, const char *newpath);
 
 #define symlink(oldpath, newpath)	pgsymlink(oldpath, newpath)
 #endif
-#endif   /* defined(WIN32) || defined(__CYGWIN__) */
 
 extern void copydir(char *fromdir, char *todir, bool recurse);
 

src/port/dirmod.c

@@ -10,7 +10,7 @@
  *	Win32 (NT, Win2k, XP).	replace() doesn't work on Win95/98/Me.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/port/dirmod.c,v 1.47 2007/01/19 16:42:24 alvherre Exp $
+ *	  $PostgreSQL: pgsql/src/port/dirmod.c,v 1.48 2007/07/12 23:28:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -103,6 +103,7 @@ fe_repalloc(void *pointer, Size size)
 	}
 	return res;
 }
+
 #endif   /* FRONTEND */
 
 
@@ -169,8 +170,14 @@ pgunlink(const char *path)
 	return 0;
 }
 
+/* We undefined these above; now redefine for possible use below */
+#define rename(from, to)		pgrename(from, to)
+#define unlink(path)			pgunlink(path)
+
+#endif   /* defined(WIN32) || defined(__CYGWIN__) */
+
 
-#ifdef WIN32					/* Cygwin has its own symlinks */
+#if defined(WIN32) && !defined(__CYGWIN__)	/* Cygwin has its own symlinks */
 
 /*
  *	pgsymlink support:
@@ -276,14 +283,8 @@ pgsymlink(const char *oldpath, const char *newpath)
 
 	return 0;
 }
-#endif   /* WIN32 */
-#endif   /* defined(WIN32) || defined(__CYGWIN__) */
-
 
-/* We undefined this above, so we redefine it */
-#if defined(WIN32) || defined(__CYGWIN__)
-#define unlink(path)	pgunlink(path)
-#endif
+#endif /* defined(WIN32) && !defined(__CYGWIN__) */
 
 
 /*