+@item
+This header file is missing on some platforms:
+Minix 3.1.8, mingw, MSVC 9, BeOS.
+@item
+The constant @code{CODESET} is not defined on some platforms:
+glibc 2.0.6, OpenBSD 3.8.
+@item
+The constants @code{ERA}, @code{ERA_D_FMT}, @code{ERA_D_T_FMT},
+@code{ERA_T_FMT}, @code{ALT_DIGITS} are not defined on some platforms:
+OpenBSD 3.8.
+@item
+The constants @code{T_FMT_AMPM}, @code{YESEXPR}, @code{NOEXPR} are not
+defined on some platforms:
+IRIX 5.3.