Add Olson's public domain timezone library to src/timezone.

src/timezone/pgtz.c

@@ -0,0 +1,42 @@
+/*-------------------------------------------------------------------------
+ *
+ * pgtz.c
+ *    Timezone Library Integration Functions
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/src/timezone/pgtz.c,v 1.1 2004/04/30 04:09:23 momjian Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "pgtz.h"
+#include "tzfile.h"
+
+
+#ifdef WIN32
+static char tzdir[MAXPGPATH];
+static int done_tzdir = 0;
+char *pgwin32_TZDIR(void) {
+	char *p;
+	if (done_tzdir)
+		return tzdir;
+
+	if (GetModuleFileName(NULL,tzdir,MAXPGPATH) == 0)
+		return NULL;
+	
+	canonicalize_path(tzdir);
+	if ((p = last_path_separator(tzdir)) == NULL)
+		return NULL;
+	else
+		*p = '\0';
+	
+	strcat(tzdir,"/../share/timezone");
+
+	done_tzdir=1;
+	return tzdir;
+}
+#else
+#error pgwin32_TZDIR not implemented on non win32 yet!
+#endif