+# Check for specific termios structures.
+AC_CHECK_TYPE([struct termios2], [AC_DEFINE(HAVE_TERMIOS2, 1)], [], [[#include <linux/termios.h>]])
+AC_CHECK_TYPE([struct termiox], [AC_DEFINE(HAVE_TERMIOX, 1)], [], [[#include <linux/termios.h>]])
+AC_CHECK_MEMBERS([struct termios.c_ispeed, struct termios.c_ospeed],
+ [AC_DEFINE(HAVE_TERMIOS_SPEED, 1)], [], [[#include <linux/termios.h>]])
+AC_CHECK_MEMBERS([struct termios2.c_ispeed, struct termios2.c_ospeed],
+ [AC_DEFINE(HAVE_TERMIOS2_SPEED, 1)], [], [[#include <linux/termios.h>]])
+
+# Check for serial_struct.
+AC_CHECK_TYPE([struct serial_struct], [AC_DEFINE(HAVE_SERIAL_STRUCT, 1)],
+ [], [[#include <linux/serial.h>]])
+
+saved="$CFLAGS"; CFLAGS="$CFLAGS -Werror"
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+ __attribute__((visibility("hidden"))) void foo(void) { }
+ ]])],
+ [AC_DEFINE(SP_API , __attribute__((visibility("default"))))]
+ [AC_DEFINE(SP_PRIV, __attribute__((visibility("hidden"))))],
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+ __declspec(dllexport) void foo(void) { }
+ ]])],
+ [AC_DEFINE(SP_API , __declspec(dllexport))]
+ [AC_DEFINE(SP_PRIV,)],
+ [AC_DEFINE(SP_API,)]
+ [AC_DEFINE(SP_PRIV,)]))
+CFLAGS="$saved"