- dnl Execute this unconditionally, because CTYPE_H may be set by other
- dnl modules, after this code is executed.
- gl_CHECK_NEXT_HEADERS([ctype.h])
+
+ dnl <ctype.h> is always overridden, because of GNULIB_POSIXCHECK.
+ gl_NEXT_HEADERS([ctype.h])
+
+ dnl Check for declarations of anything we want to poison if the
+ dnl corresponding gnulib module is not in use.
+ gl_WARN_ON_USE_PREPARE([[#include <ctype.h>
+ ]], [isblank])