+AC_ARG_WITH([twin],
+ [AS_HELP_STRING([--with-twin],
+ [build GUI versions using the twin window system])],
+ [],
+ [with_twin=check])
+
+LIBTWIN=
+AS_IF([test "x$with_twin" != xno],
+ [PKG_CHECK_MODULES([twin], [libtwin], [],
+ [AC_MSG_RESULT([$twin_PKG_ERRORS])
+ AC_MSG_RESULT([Consider adjusting PKG_CONFIG_PATH environment variable])])
+ AC_CHECK_LIB([twin], [main],
+ [AC_SUBST([LIBTWIN], ["-ltwin"])
+ AC_DEFINE([HAVE_LIBTWIN], [1], [Define if you have libtwin])],
+ [if test "x$with_twin" != xcheck; then
+ AC_MSG_FAILURE([--with-twin was given, but test for twin failed])
+ fi],
+ [${twin_LIBS}])])
+