[LyX/master] Get rid of boost signals in multithreading test

[Georg Baum]

commit 7293fc7b66aebb9339c25ba87c4acf4f87f49973
Author: Georg Baum <b...@lyx.org>
Date:   Sat Jun 11 09:04:50 2016 +0200

    Get rid of boost signals in multithreading test
    
    Test for regex instead since this is the only boost library we are linking 
against.

diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index 07153ec..227dd93 100644
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -398,20 +398,19 @@ AC_DEFUN([LYX_USE_INCLUDED_BOOST],[
            AC_LANG_PUSH(C++)
            save_LIBS=$LIBS
 
-           dnl FIXME: Rewrite test to use regex, we do not use signals anymore.
            AC_MSG_CHECKING([for multithreaded boost libraries])
-           LIBS="$save_LIBS -lboost_signals-mt $LIBTHREAD"
+           LIBS="$save_LIBS -lboost_regex-mt $LIBTHREAD"
            AC_LINK_IFELSE(
-               [AC_LANG_PROGRAM([#include <boost/signal.hpp>],
-                       [boost::signal<void ()> s;])],
+               [AC_LANG_PROGRAM([#include <boost/regex.hpp>],
+                       [boost::regex reg;])],
                [AC_MSG_RESULT([yes])
                 BOOST_MT="-mt"],
                [AC_MSG_RESULT([no])
                 AC_MSG_CHECKING([for plain boost libraries])
-                LIBS="$save_LIBS -lboost_signals"
+                LIBS="$save_LIBS -lboost_regex"
                 AC_LINK_IFELSE(
-                    [AC_LANG_PROGRAM([#include <boost/signal.hpp>],
-                            [boost::signal<void ()> s;])],
+                    [AC_LANG_PROGRAM([#include <boost/regex.hpp>],
+                            [boost::regex reg;])],
                     [AC_MSG_RESULT([yes])
                      BOOST_MT=""],
                     [AC_MSG_RESULT([no])