Fix genflags compilation error.

* lib/genflags.c (ICONV_SURFACE_EBCDIC_ZOS_UNIX): New macro, copied from
include/iconv.h.in.
diff --git a/ChangeLog b/ChangeLog
index 7d488e8..d76dff0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2023-04-03  Bruno Haible  <bruno@clisp.org>
 
+	Fix genflags compilation error.
+	* lib/genflags.c (ICONV_SURFACE_EBCDIC_ZOS_UNIX): New macro, copied from
+	include/iconv.h.in.
+
 	Allow overriding the newline conversion for EBCDIC encodings.
 	Reported by Mike Fulton <mikefultonpersonal@gmail.com> in
 	<https://lists.gnu.org/archive/html/bug-gnu-libiconv/2023-04/msg00009.html>.
diff --git a/lib/genflags.c b/lib/genflags.c
index 66732be..9f3d15d 100644
--- a/lib/genflags.c
+++ b/lib/genflags.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2000-2002, 2005-2006, 2008-2009, 2016, 2022 Free Software Foundation, Inc.
+/* Copyright (C) 2000-2002, 2005-2006, 2008-2009, 2016, 2022-2023 Free Software Foundation, Inc.
    This file is part of the GNU LIBICONV Library.
 
    The GNU LIBICONV Library is free software; you can redistribute it
@@ -35,8 +35,9 @@
 #define USE_EXTRA
 
 struct loop_funcs {};
-struct iconv_fallbacks {};
 struct iconv_hooks {};
+struct iconv_fallbacks {};
+#define ICONV_SURFACE_EBCDIC_ZOS_UNIX  1
 #include "converters.h"
 
 static void emit_encoding (struct wctomb_funcs * ofuncs, const char* c_name)