.Pp
.Nm
is intended to be portable to any system with a working C implementation that
-at least makes an effort to support C99. The library maintains no global state
-and thus all functions should be safe for use in a multi-threaded environment.
+at least makes an effort to support C99. The library is thread-safe when
+appropriate facilities exist and are enabled at build time.
.Sh ABSTRACT SYNTAX TREE
The functions in
.Nm