tests: Conditional compilation of tests (including boost-based unit tests)

To compile tests, code needs to be configured with --with-tests option,
otherwise all tests are disabled.

Tests that are based on Boost's unit test framework are enabled only if
the framework is detected during the configure time.

Change-Id: Ia1768e24b088e4f19d2a8799c6d5baeabb2f44c5
diff --git a/m4/ax_boost_asio.m4 b/m4/ax_boost_asio.m4
new file mode 100644
index 0000000..b57d487
--- /dev/null
+++ b/m4/ax_boost_asio.m4
@@ -0,0 +1,110 @@
+# ===========================================================================
+#       http://www.gnu.org/software/autoconf-archive/ax_boost_asio.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_BOOST_ASIO
+#
+# DESCRIPTION
+#
+#   Test for Asio library from the Boost C++ libraries. The macro requires a
+#   preceding call to AX_BOOST_BASE. Further documentation is available at
+#   <http://randspringer.de/boost/index.html>.
+#
+#   This macro calls:
+#
+#     AC_SUBST(BOOST_ASIO_LIB)
+#
+#   And sets:
+#
+#     HAVE_BOOST_ASIO
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Thomas Porschberg <thomas@randspringer.de>
+#   Copyright (c) 2008 Pete Greenwell <pete@mu.org>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 16
+
+AC_DEFUN([AX_BOOST_ASIO],
+[
+	AC_ARG_WITH([boost-asio],
+	AS_HELP_STRING([--with-boost-asio@<:@=special-lib@:>@],
+                   [use the ASIO library from boost - it is possible to specify a certain library for the linker
+                        e.g. --with-boost-asio=boost_system-gcc41-mt-1_34 ]),
+        [
+        if test "$withval" = "no"; then
+			want_boost="no"
+        elif test "$withval" = "yes"; then
+            want_boost="yes"
+            ax_boost_user_asio_lib=""
+        else
+		    want_boost="yes"
+		ax_boost_user_asio_lib="$withval"
+		fi
+        ],
+        [want_boost="yes"]
+	)
+
+	if test "x$want_boost" = "xyes"; then
+        AC_REQUIRE([AC_PROG_CC])
+		CPPFLAGS_SAVED="$CPPFLAGS"
+		CPPFLAGS="$CPPFLAGS $BOOST_CPPFLAGS"
+		export CPPFLAGS
+
+		LDFLAGS_SAVED="$LDFLAGS"
+		LDFLAGS="$LDFLAGS $BOOST_LDFLAGS"
+		export LDFLAGS
+
+        AC_CACHE_CHECK(whether the Boost::ASIO library is available,
+					   ax_cv_boost_asio,
+        [AC_LANG_PUSH([C++])
+		 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ @%:@include <boost/asio.hpp>
+											]],
+                                  [[
+
+                                    boost::asio::io_service io;
+                                    boost::system::error_code timer_result;
+                                    boost::asio::deadline_timer t(io);
+                                    t.cancel();
+                                    io.run_one();
+									return 0;
+                                   ]])],
+                             ax_cv_boost_asio=yes, ax_cv_boost_asio=no)
+         AC_LANG_POP([C++])
+		])
+		if test "x$ax_cv_boost_asio" = "xyes"; then
+			AC_DEFINE(HAVE_BOOST_ASIO,,[define if the Boost::ASIO library is available])
+			BN=boost_system
+			BOOSTLIBDIR=`echo $BOOST_LDFLAGS | sed -e 's/@<:@^\/@:>@*//'`
+            if test "x$ax_boost_user_asio_lib" = "x"; then
+				for ax_lib in `ls $BOOSTLIBDIR/libboost_system*.so* $BOOSTLIBDIR/libboost_system*.dylib* $BOOSTLIBDIR/libboost_system*.a* 2>/dev/null | sed 's,.*/,,' | sed -e 's;^lib\(boost_system.*\)\.so.*$;\1;' -e 's;^lib\(boost_system.*\)\.dylib.*$;\1;' -e 's;^lib\(boost_system.*\)\.a.*$;\1;' ` ; do
+				    AC_CHECK_LIB($ax_lib, main, [BOOST_ASIO_LIB="-l$ax_lib" AC_SUBST(BOOST_ASIO_LIB) link_thread="yes" break],
+                                 [link_thread="no"])
+				done
+            else
+               for ax_lib in $ax_boost_user_asio_lib $BN-$ax_boost_user_asio_lib; do
+				      AC_CHECK_LIB($ax_lib, main,
+                                   [BOOST_ASIO_LIB="-l$ax_lib" AC_SUBST(BOOST_ASIO_LIB) link_asio="yes" break],
+                                   [link_asio="no"])
+                  done
+
+            fi
+            if test "x$ax_lib" = "x"; then
+                AC_MSG_ERROR(Could not find a version of the library!)
+            fi
+			if test "x$link_asio" = "xno"; then
+				AC_MSG_ERROR(Could not link against $ax_lib !)
+			fi
+		fi
+
+		CPPFLAGS="$CPPFLAGS_SAVED"
+	LDFLAGS="$LDFLAGS_SAVED"
+	fi
+])