diff --git a/Modules/_ctypes/libffi/src/alpha/ffi.c b/Modules/_ctypes/libffi/src/alpha/ffi.c
index 00d3379..cd34d8b 100644
--- a/Modules/_ctypes/libffi/src/alpha/ffi.c
+++ b/Modules/_ctypes/libffi/src/alpha/ffi.c
@@ -28,7 +28,7 @@
 
 #include <stdlib.h>
 
-extern void ffi_call_osf(void *, unsigned long, unsigned, void *, void (*)());
+extern void ffi_call_osf(void *, unsigned long, unsigned, void *, void (*)(void));
 extern void ffi_closure_osf(void);
 
 
@@ -58,7 +58,7 @@
 }
 
 void
-ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
+ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 {
   unsigned long *stack, *argp;
   long i, avn;
diff --git a/Modules/_ctypes/libffi/src/ia64/ffi.c b/Modules/_ctypes/libffi/src/ia64/ffi.c
index e810827..ca26ca3 100644
--- a/Modules/_ctypes/libffi/src/ia64/ffi.c
+++ b/Modules/_ctypes/libffi/src/ia64/ffi.c
@@ -259,10 +259,10 @@
   return FFI_OK;
 }
 
-extern int ffi_call_unix (struct ia64_args *, PTR64, void (*)(), UINT64);
+extern int ffi_call_unix (struct ia64_args *, PTR64, void (*)(void), UINT64);
 
 void
-ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
+ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 {
   struct ia64_args *stack;
   long i, avn, gpcount, fpcount;
@@ -387,7 +387,7 @@
    gp pointer to the closure.  This allows the function entry code to
    both retrieve the user data, and to restire the correct gp pointer.  */
 
-extern void ffi_closure_unix ();
+extern void ffi_closure_unix (void);
 
 ffi_status
 ffi_prep_closure (ffi_closure* closure,
diff --git a/Modules/_ctypes/libffi/src/mips/ffi.c b/Modules/_ctypes/libffi/src/mips/ffi.c
index 73bc952..e11801d 100644
--- a/Modules/_ctypes/libffi/src/mips/ffi.c
+++ b/Modules/_ctypes/libffi/src/mips/ffi.c
@@ -445,14 +445,14 @@
 /* Low level routine for calling O32 functions */
 extern int ffi_call_O32(void (*)(char *, extended_cif *, int, int), 
 			extended_cif *, unsigned, 
-			unsigned, unsigned *, void (*)());
+			unsigned, unsigned *, void (*)(void));
 
 /* Low level routine for calling N32 functions */
 extern int ffi_call_N32(void (*)(char *, extended_cif *, int, int), 
 			extended_cif *, unsigned, 
-			unsigned, unsigned *, void (*)());
+			unsigned, unsigned *, void (*)(void));
 
-void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
+void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 {
   extended_cif ecif;
 
diff --git a/Modules/_ctypes/libffi/src/pa/ffi.c b/Modules/_ctypes/libffi/src/pa/ffi.c
index f6264db..373b427 100644
--- a/Modules/_ctypes/libffi/src/pa/ffi.c
+++ b/Modules/_ctypes/libffi/src/pa/ffi.c
@@ -345,12 +345,12 @@
 			   /*@out@*/ extended_cif *,
 			   unsigned, unsigned,
 			   /*@out@*/ unsigned *,
-			   void (*fn)());
+			   void (*fn)(void));
 /*@=declundef@*/
 /*@=exportheader@*/
 
 void ffi_call(/*@dependent@*/ ffi_cif *cif,
-	      void (*fn)(),
+	      void (*fn)(void),
 	      /*@out@*/ void *rvalue,
 	      /*@dependent@*/ void **avalue)
 {
diff --git a/Modules/_ctypes/libffi/src/powerpc/ffi.c b/Modules/_ctypes/libffi/src/powerpc/ffi.c
index bfd7ab6..5b9ed86 100644
--- a/Modules/_ctypes/libffi/src/powerpc/ffi.c
+++ b/Modules/_ctypes/libffi/src/powerpc/ffi.c
@@ -756,17 +756,17 @@
 extern void ffi_call_SYSV(/*@out@*/ extended_cif *,
 			  unsigned, unsigned,
 			  /*@out@*/ unsigned *,
-			  void (*fn)());
+			  void (*fn)(void));
 extern void FFI_HIDDEN ffi_call_LINUX64(/*@out@*/ extended_cif *,
 					unsigned long, unsigned long,
 					/*@out@*/ unsigned long *,
-					void (*fn)());
+					void (*fn)(void));
 /*@=declundef@*/
 /*@=exportheader@*/
 
 void
 ffi_call(/*@dependent@*/ ffi_cif *cif,
-	 void (*fn)(),
+	 void (*fn)(void),
 	 /*@out@*/ void *rvalue,
 	 /*@dependent@*/ void **avalue)
 {
diff --git a/Modules/_ctypes/libffi/src/s390/ffi.c b/Modules/_ctypes/libffi/src/s390/ffi.c
index 399fa2a..3d25b6f 100644
--- a/Modules/_ctypes/libffi/src/s390/ffi.c
+++ b/Modules/_ctypes/libffi/src/s390/ffi.c
@@ -88,7 +88,7 @@
 			  void (*)(unsigned char *, extended_cif *),
 			  unsigned,
 			  void *,
-			  void (*fn)());
+			  void (*fn)(void));
 
 extern void ffi_closure_SYSV(void);
  
@@ -480,7 +480,7 @@
  
 void
 ffi_call(ffi_cif *cif,
-	 void (*fn)(),
+	 void (*fn)(void),
 	 void *rvalue,
 	 void **avalue)
 {
diff --git a/Modules/_ctypes/libffi/src/sparc/ffi.c b/Modules/_ctypes/libffi/src/sparc/ffi.c
index b83d63d..a045e01 100644
--- a/Modules/_ctypes/libffi/src/sparc/ffi.c
+++ b/Modules/_ctypes/libffi/src/sparc/ffi.c
@@ -358,13 +358,13 @@
 
 #ifdef SPARC64
 extern int ffi_call_v9(void *, extended_cif *, unsigned, 
-		       unsigned, unsigned *, void (*fn)());
+		       unsigned, unsigned *, void (*fn)(void));
 #else
 extern int ffi_call_v8(void *, extended_cif *, unsigned, 
-		       unsigned, unsigned *, void (*fn)());
+		       unsigned, unsigned *, void (*fn)(void));
 #endif
 
-void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
+void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
 {
   extended_cif ecif;
   void *rval = rvalue;