Use correct ifdef test for cygwin, namely __CYGWIN__ (note underscores).

src/test/regress/pg_regress.c

@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.13 2006/07/24 01:50:22 adunstan Exp $
+ * $PostgreSQL: pgsql/src/test/regress/pg_regress.c,v 1.14 2006/07/25 01:37:42 adunstan Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -437,7 +437,7 @@ initialize_environment(void)
 	unsetenv("LANG");
 	unsetenv("LANGUAGE");
 	/* On Windows the default locale may not be English, so force it */
-#if defined(WIN32) || defined(CYGWIN)
+#if defined(WIN32) || defined(__CYGWIN__)
 	putenv("LANG=en");
 #endif
 
@@ -513,7 +513,7 @@ initialize_environment(void)
 		 */
 		add_to_path("LD_LIBRARY_PATH", ':', libdir);
 		add_to_path("DYLD_LIBRARY_PATH", ':', libdir);
-#if defined(WIN32) || defined(CYGWIN)
+#if defined(WIN32) || defined(__CYGWIN__)
 		add_to_path("PATH", ';', libdir);
 #endif
 	}