diff --git a/src/include/storage/s_lock.h b/src/include/storage/s_lock.h
index 455329dce0dc4371f770dad04c3a97756bc89450..f90afed5deec83d418c092ffa41eb03ba87274ac 100644
--- a/src/include/storage/s_lock.h
+++ b/src/include/storage/s_lock.h
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/include/storage/s_lock.h,v 1.25 1998/02/13 05:09:50 scrappy Exp $
+ *	  $Header: /cvsroot/pgsql/src/include/storage/s_lock.h,v 1.26 1998/02/13 17:11:55 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -141,7 +141,7 @@ static int	tas(slock_t *lock);
  * (see storage/ipc.h).
  */
 
-#if defined(__AIX)
+#if defined(_AIX)
 
 #define	S_LOCK(lock)	do \
 						{ \
@@ -153,7 +153,7 @@ static int	tas(slock_t *lock);
 
 #define	S_INIT_LOCK(lock)	S_UNLOCK(lock)
 
-#endif							/* __AIX */
+#endif							/* _AIX */
 
 /*
  * HP-UX (PA-RISC)
diff --git a/src/include/utils/dt.h b/src/include/utils/dt.h
index 8e26f0b0b3588fe51656365d9b089f8f94ae520b..fe583b8641c1316bff68fd93e0b8ad92da361951 100644
--- a/src/include/utils/dt.h
+++ b/src/include/utils/dt.h
@@ -8,7 +8,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: dt.h,v 1.26 1998/02/03 02:09:02 scrappy Exp $
+ * $Id: dt.h,v 1.27 1998/02/13 17:12:07 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -187,11 +187,11 @@ typedef struct
 /* keep this struct small; it gets used a lot */
 typedef struct
 {
-#if defined(__AIX)
+#if defined(_AIX)
 	char	   *token;
 #else
 	char		token[TOKMAXLEN];
-#endif							/* __AIX */
+#endif							/* _AIX */
 	char		type;
 	char		value;			/* this may be unsigned, alas */
 } datetkn;
diff --git a/src/include/utils/nabstime.h b/src/include/utils/nabstime.h
index 441a095fda67d990ddd4afe1655e5a21ae573e17..16a0221493c495c9d3099dacf1d727c60cb45eab 100644
--- a/src/include/utils/nabstime.h
+++ b/src/include/utils/nabstime.h
@@ -6,7 +6,7 @@
  *
  * Copyright (c) 1994, Regents of the University of California
  *
- * $Id: nabstime.h,v 1.14 1998/02/03 02:09:08 scrappy Exp $
+ * $Id: nabstime.h,v 1.15 1998/02/13 17:12:08 scrappy Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,7 +53,7 @@ typedef TimeIntervalData *TimeInterval;
 #define BIG_ABSTIME		((AbsoluteTime) 0x7FFFFFFB)		/* 2147483644 == 2^31 -
 														 * 4 */
 
-#if defined(__AIX)
+#if defined(_AIX)
 /*
  * AIX considers 2147483648 == -2147483648 (since they have the same bit
  * representation) but uses a different sign sense in a comparison to
@@ -63,7 +63,7 @@ typedef TimeIntervalData *TimeInterval;
 #define NOSTART_ABSTIME		 ((AbsoluteTime) INT_MIN)
 #else
 #define NOSTART_ABSTIME ((AbsoluteTime) 0x80000001)		/* -2147483647 == - 2^31 */
-#endif							/* __AIX */
+#endif							/* _AIX */
 
 #define INVALID_RELTIME ((RelativeTime) 0x7FFFFFFE)		/* 2147483647 == 2^31 -
 														 * 1 */