$OpenBSD: patch-configure_ac,v 1.3 2015/12/21 20:58:57 naddy Exp $

AC_CHECK_HEADERS_ONCE() cannot be conditionalized.

--- configure.ac.orig	Wed Nov 18 06:31:35 2015
+++ configure.ac	Mon Dec 21 21:46:52 2015
@@ -656,9 +656,9 @@ AC_MSG_RESULT(no),
 AC_MSG_WARN([*** Can't check for macro redefinability when cross-compiling]))
 
 AS_IF([test "x$enable_libmagic" != "xno"], [
-  AC_CHECK_HEADERS_ONCE([magic.h])
+  AC_CHECK_HEADERS([magic.h])
   AC_CHECK_LIB(magic, magic_open)
-  AC_CHECK_HEADERS_ONCE([zlib.h])
+  AC_CHECK_HEADERS([zlib.h])
   AC_CHECK_LIB(z, inflate)
 ])
 
