diff --git a/src/csplit.c b/src/csplit.c
index 798d6509c..5765b941a 100644
--- a/src/csplit.c
+++ b/src/csplit.c
@@ -119,14 +119,6 @@ struct buffer_record
   struct buffer_record *next;
 };
 
-#ifndef __P
-# if PROTOTYPES
-#  define __P(Args) Args
-# else
-#  define __P(Args) ()
-# endif
-#endif
-
 int safe_read ();
 
 static void close_output_file __P ((void));
diff --git a/src/fmt.c b/src/fmt.c
index 16fbca44b..f4d616185 100644
--- a/src/fmt.c
+++ b/src/fmt.c
@@ -142,14 +142,6 @@ struct Word
 
 /* Forward declarations.  */
 
-#ifndef __P
-# if PROTOTYPES
-#  define __P(Args) Args
-# else
-#  define __P(Args) ()
-# endif
-#endif
-
 static void set_prefix __P ((char *p));
 static void fmt __P ((FILE *f));
 static bool get_paragraph __P ((FILE *f));
diff --git a/src/pr.c b/src/pr.c
index 874f6f5f9..465a06c16 100644
--- a/src/pr.c
+++ b/src/pr.c
@@ -179,14 +179,6 @@ typedef struct COLUMN COLUMN;
 
 #define NULLCOL (COLUMN *)0
 
-#ifndef __P
-# if PROTOTYPES
-#  define __P(Args) Args
-# else
-#  define __P(Args) ()
-# endif
-#endif
-
 static int char_to_clump __P ((int c));
 static int read_line __P ((COLUMN *p));
 static int print_page __P ((void));