diff --git a/m4/boost.m4 b/m4/boost.m4
index 706035d31c9aefcba52ceacb839ab2f3ee0168d5..342516e445312787f87a88742c23c603c2d22a12 100644
--- a/m4/boost.m4
+++ b/m4/boost.m4
@@ -1332,11 +1332,16 @@ BOOST_DEFUN([String_Algo],
 # --------------------------------
 # Look for Boost.System.  For the documentation of PREFERRED-RT-OPT, see the
 # documentation of BOOST_FIND_LIB above.  This library was introduced in Boost
-# 1.35.0.
+# 1.35.0 and is header only since 1.70.
 BOOST_DEFUN([System],
-[BOOST_FIND_LIB([system], [$1],
+[
+if test $boost_major_version -ge 170; then
+  BOOST_FIND_HEADER([boost/system/error_code.hpp])
+else
+  BOOST_FIND_LIB([system], [$1],
                 [boost/system/error_code.hpp],
                 [boost::system::error_code e; e.clear();], [], [], [$2])
+fi
 ])# BOOST_SYSTEM