POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/iswblank.html}
-Gnulib module: wctype
+Gnulib module: iswblank
Portability problems fixed by Gnulib:
@itemize
This function is declared but not defined on some platforms:
IRIX 6.5.30.
@item
+This function is not declared (without @code{-D_GNU_SOURCE}) on some platforms:
+glibc 2.8.
+@item
This function returns 0 for all possible arguments on some platforms:
Linux libc5.
@end itemize