tests/struct_flock.c: fix musl libc compilation warnings
The size of off_t is not something one can rely upon. For example,
musl libc unconditionally defines it as an int64_t type on x86.
A cast to the target type helps to avoid these libc differences.
* configure.ac: Call AC_C_TYPEOF.
* tests/struct_flock.c (TYPEOF_FLOCK_OFF_T): New macro.
(test_flock_einval): Use it instead of off_t.
diff --git a/configure.ac b/configure.ac
index 1524b9b..42a6acc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
#
# Copyright (c) 1999-2001 Wichert Akkerman <wichert@deephackmode.org>
# Copyright (c) 2002-2009 Roland McGrath <roland@redhat.com>
-# Copyright (c) 2006-2015 Dmitry V. Levin <ldv@altlinux.org>
+# Copyright (c) 2006-2016 Dmitry V. Levin <ldv@altlinux.org>
# Copyright (c) 2008-2015 Mike Frysinger <vapier@gentoo.org>
# Copyright (c) 2015 Elvira Khabirova <lineprinter0@gmail.com>
# All rights reserved.
@@ -251,6 +251,7 @@
AC_PROG_INSTALL
AC_C_CONST
AC_C_BIGENDIAN
+AC_C_TYPEOF
AC_HEADER_STDC
AC_HEADER_STDBOOL
AC_HEADER_DIRENT