-# lseek.m4 serial 7
+# lseek.m4 serial 8
dnl Copyright (C) 2007, 2009-2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([AC_PROG_CC])
+ AC_CHECK_HEADERS_ONCE([unistd.h])
AC_CACHE_CHECK([whether lseek detects pipes], [gl_cv_func_lseek_pipe],
[if test $cross_compiling = no; then
AC_LINK_IFELSE([AC_LANG_PROGRAM([[
#include <sys/types.h> /* for off_t */
#include <stdio.h> /* for SEEK_CUR */
-#include <unistd.h>]], [[
+#if HAVE_UNISTD_H
+# include <unistd.h>
+#else /* on Windows with MSVC */
+# include <io.h>
+#endif
+]], [[
/* Exit with success only if stdin is seekable. */
return lseek (0, (off_t)0, SEEK_CUR) < 0;
]])],