Build: Require Boost.Asio to be v1.69.0+

configure.ac

@@ -32,7 +32,7 @@ AC_DEFINE_UNQUOTED([CONFIG_MIND_VOSCILLATOR_FREQ_MS],
     [Frequency of the mind virtual oscillator in milliseconds])
 
 m4_include([m4/ax_boost_base.m4])
-m4_include([m4/ax_boost_asio.m4])
+m4_include([m4/ax_boost_asio_1.69.0.m4])
 m4_include([m4/ac_prog_flex.m4])
 m4_include([m4/ac_prog_bison.m4])
 AC_PROG_CC
@@ -44,9 +44,10 @@ AC_PROG_YACC
 AS_IF([test -z "${LEX}" || test -z "${YACC}"], [
     AC_MSG_ERROR([LEX and YACC must both be available in PATH.])
 ])
-#AX_BOOST_BASE
-AX_BOOST_ASIO
-AS_IF([test "x${HAVE_BOOST_ASIO}" != "xyes"], [
+AX_BOOST_BASE([1.69.0], [], [AC_MSG_ERROR(m4_normalize([Boost v1.69.0 or higher
+    is required, because Boost.System is header-only from 1.69.0 onwards.]))])
+AX_BOOST_ASIO_gte_1_69_0
+AS_IF([test "x${HAVE_BOOST_ASIO}" == "x"], [
     AC_MSG_ERROR(m4_normalize([Boost.Asio must be available in headers.
         Try --with-boost-asio if need be.]))
 ])

m4/ax_boost_asio_1.69.0.m4

@@ -32,7 +32,7 @@
 
 #serial 18
 
-AC_DEFUN([AX_BOOST_ASIO],
+AC_DEFUN([AX_BOOST_ASIO_gte_1_69_0],
 [
 	AC_ARG_WITH([boost-asio],
 	AS_HELP_STRING([--with-boost-asio@<:@=special-lib@:>@],
@@ -80,28 +80,13 @@ AC_DEFUN([AX_BOOST_ASIO],
          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$ax_lib" = "x"; then
-                AC_MSG_ERROR(Could not find a version of the Boost::Asio library!)
-            fi
-			if test "x$link_asio" = "xno"; then
-				AC_MSG_ERROR(Could not link against $ax_lib !)
-			fi
+			AC_DEFINE(HAVE_BOOST_ASIO,,
+				[define if the Boost::ASIO library is available])
+			BOOST_ASIO_LIB=""
+			AC_SUBST(BOOST_ASIO_LIB)
+			HAVE_BOOST_ASIO="yes"
+		else
+			HAVE_BOOST_ASIO="no"
 		fi
 
 		CPPFLAGS="$CPPFLAGS_SAVED"