Introduce and use function typedef pem_password_cb so that we don't call
those functions without having a parameter list declaration.
(There are various similar cases left ...)
diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 666dba5..09c837c 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -1115,7 +1115,7 @@
 	Free((char *)a);
 	}
 
-void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx,int (*cb)())
+void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx, pem_password_cb *cb)
 	{
 	ctx->default_passwd_callback=cb;
 	}