+# RADIUSCLIENT is the radiusclient library; you probably need to add
+# -lradiusclient to EXTRALIBS.
+#
+# The API for the radiusclient library was changed at release 0.4.0.
+# Unfortunately, the header file does not define a version number that clients
+# can use to support both the old and new APIs. If you are using version 0.4.0
+# or later of the radiusclient library, you should use RADIUSCLIENTNEW.
+#
+# RADLIB is the Radius library that comes with FreeBSD (the header file is
+# called radlib.h); you probably need to add -lradius to EXTRALIBS.
+#
+# If you do not set RADIUS_LIB_TYPE, Exim assumes the radiusclient library,
+# using the original API.