This header file is not self-contained on some platforms:
OSF/1 with Desktop Toolkit C, BSD/OS 4.0.1.
@item
-The type @code{wint_t} is missing on some platforms:
+The type @code{wint_t} and macro @code{WEOF} are missing on some platforms:
IRIX 5.3.
+
+@item
+Some platforms provide a @code{NULL} macro that cannot be used in arbitrary
+expressions:
+NetBSD 5.0
@end itemize
Portability problems not fixed by Gnulib:
@itemize
+@item
+This header file leads to link errors and endless recursions or endless loops
+on some platforms:
+glibc version 2.5 or older, together with gcc version 4.3 or newer and the
+option @samp{-std=c99} or @samp{-std=gnu99}.
@end itemize