--- libs/chrono/build/Jamfile.v2.orig	2019-04-09 21:35:24.000000000 +0200
+++ libs/chrono/build/Jamfile.v2	2020-06-30 15:23:16.850342000 +0200
@@ -12,6 +12,7 @@
     : source-location ../src
     : requirements
         <target-os>freebsd:<linkflags>"-lrt"
+        <target-os>bsdsunix:<linkflags>"-lrt"
         <target-os>linux:<linkflags>"-lrt -lpthread"
         <toolset>pgi:<linkflags>"-lrt"
         #<threading>single:<define>BOOST_CHRONO_THREAD_DISABLED