--- a/meson.build	2019-04-29 22:00:08.000000000 +0200
+++ b/meson.build	2019-04-29 22:00:20.000000000 +0200
@@ -127,6 +127,9 @@
 
   # disable deprecated boost::system features
   '-DBOOST_SYSTEM_NO_DEPRECATED',
+  
+  # workaround for 1.66 on macOS >= 10.14
+  '-DBOOST_ASIO_HAS_STD_STRING_VIEW',
 ]
 
 test_cflags = [