# Check for serial_struct.
AC_CHECK_TYPES([struct serial_struct],,, [[#include <linux/serial.h>]])
+# Check for realpath().
+AC_CHECK_FUNC([realpath], [AC_DEFINE(HAVE_REALPATH, 1, [realpath is available.])], [])
+
+# Check for clock_gettime().
+AC_CHECK_FUNC([clock_gettime],
+ [AC_DEFINE(HAVE_CLOCK_GETTIME, 1, [clock_gettime is available.])], [])
+
AC_CACHE_CHECK([for visibility control], [sp_cv_visibility_control], [
sp_saved_CFLAGS=$CFLAGS
CFLAGS="$CFLAGS -Werror"