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_system.m4 b/m4/ax_boost_system.m4
new file mode 100644
index 0000000..c4c4555
--- /dev/null
+++ b/m4/ax_boost_system.m4
@@ -0,0 +1,120 @@
+# ===========================================================================
+#      http://www.gnu.org/software/autoconf-archive/ax_boost_system.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_BOOST_SYSTEM
+#
+# DESCRIPTION
+#
+#   Test for System 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_SYSTEM_LIB)
+#
+#   And sets:
+#
+#     HAVE_BOOST_SYSTEM
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Thomas Porschberg <thomas@randspringer.de>
+#   Copyright (c) 2008 Michael Tindal
+#   Copyright (c) 2008 Daniel Casimiro <dan.casimiro@gmail.com>
+#
+#   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 17
+
+AC_DEFUN([AX_BOOST_SYSTEM],
+[
+	AC_ARG_WITH([boost-system],
+	AS_HELP_STRING([--with-boost-system@<:@=special-lib@:>@],
+                   [use the System library from boost - it is possible to specify a certain library for the linker
+                        e.g. --with-boost-system=boost_system-gcc-mt ]),
+        [
+        if test "$withval" = "no"; then
+			want_boost="no"
+        elif test "$withval" = "yes"; then
+            want_boost="yes"
+            ax_boost_user_system_lib=""
+        else
+		    want_boost="yes"
+		ax_boost_user_system_lib="$withval"
+		fi
+        ],
+        [want_boost="yes"]
+	)
+
+	if test "x$want_boost" = "xyes"; then
+        AC_REQUIRE([AC_PROG_CC])
+        AC_REQUIRE([AC_CANONICAL_BUILD])
+		CPPFLAGS_SAVED="$CPPFLAGS"
+		CPPFLAGS="$CPPFLAGS $BOOST_CPPFLAGS"
+		export CPPFLAGS
+
+		LDFLAGS_SAVED="$LDFLAGS"
+		LDFLAGS="$LDFLAGS $BOOST_LDFLAGS"
+		export LDFLAGS
+
+        AC_CACHE_CHECK(whether the Boost::System library is available,
+					   ax_cv_boost_system,
+        [AC_LANG_PUSH([C++])
+			 CXXFLAGS_SAVE=$CXXFLAGS
+
+			 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <boost/system/error_code.hpp>]],
+                                   [[boost::system::system_category]])],
+                   ax_cv_boost_system=yes, ax_cv_boost_system=no)
+			 CXXFLAGS=$CXXFLAGS_SAVE
+             AC_LANG_POP([C++])
+		])
+		if test "x$ax_cv_boost_system" = "xyes"; then
+			AC_SUBST(BOOST_CPPFLAGS)
+
+			AC_DEFINE(HAVE_BOOST_SYSTEM,,[define if the Boost::System library is available])
+            BOOSTLIBDIR=`echo $BOOST_LDFLAGS | sed -e 's/@<:@^\/@:>@*//'`
+
+			LDFLAGS_SAVE=$LDFLAGS
+            if test "x$ax_boost_user_system_lib" = "x"; then
+                for libextension in `ls -r $BOOSTLIBDIR/libboost_system* 2>/dev/null | sed 's,.*/lib,,' | sed 's,\..*,,'` ; do
+                     ax_lib=${libextension}
+				    AC_CHECK_LIB($ax_lib, exit,
+                                 [BOOST_SYSTEM_LIB="-l$ax_lib"; AC_SUBST(BOOST_SYSTEM_LIB) link_system="yes"; break],
+                                 [link_system="no"])
+				done
+                if test "x$link_system" != "xyes"; then
+                for libextension in `ls -r $BOOSTLIBDIR/boost_system* 2>/dev/null | sed 's,.*/,,' | sed -e 's,\..*,,'` ; do
+                     ax_lib=${libextension}
+				    AC_CHECK_LIB($ax_lib, exit,
+                                 [BOOST_SYSTEM_LIB="-l$ax_lib"; AC_SUBST(BOOST_SYSTEM_LIB) link_system="yes"; break],
+                                 [link_system="no"])
+				done
+                fi
+
+            else
+               for ax_lib in $ax_boost_user_system_lib boost_system-$ax_boost_user_system_lib; do
+				      AC_CHECK_LIB($ax_lib, exit,
+                                   [BOOST_SYSTEM_LIB="-l$ax_lib"; AC_SUBST(BOOST_SYSTEM_LIB) link_system="yes"; break],
+                                   [link_system="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_system" = "xno"; then
+				AC_MSG_ERROR(Could not link against $ax_lib !)
+			fi
+		fi
+
+		CPPFLAGS="$CPPFLAGS_SAVED"
+	LDFLAGS="$LDFLAGS_SAVED"
+	fi
+])