-This function is missing on some platforms:
-MacOS X 10.3, AIX 5.1, HP-UX 11.
+This function has problems with a NaN argument on some platforms:
+NetBSD 5.1, OpenBSD 4.9, Solaris 9, Cygwin.
+@item
+This function has problems with infinite arguments on some platforms:
+IRIX 6.5, OSF/1 5.1, mingw.
+@end itemize
+
+Portability problems not fixed by Gnulib:
+@itemize