-# Prerequisites of lib/strndup.c.
-AC_DEFUN([gl_PREREQ_STRNDUP], [
- AC_REQUIRE([AC_HEADER_STDC])
- AC_CHECK_DECLS(strnlen)
+ if test $ac_cv_func_strndup = yes; then
+ HAVE_STRNDUP=1
+ # AIX 4.3.3, AIX 5.1 have a function that fails to add the terminating '\0'.
+ AC_CACHE_CHECK([for working strndup], [gl_cv_func_strndup_works],
+ [AC_RUN_IFELSE([
+ AC_LANG_PROGRAM([[#include <string.h>
+ #include <stdlib.h>]], [[
+#if !HAVE_DECL_STRNDUP
+ extern
+ #ifdef __cplusplus
+ "C"
+ #endif
+ char *strndup (const char *, size_t);
+#endif
+ char *s;
+ s = strndup ("some longer string", 15);
+ free (s);
+ s = strndup ("shorter string", 13);
+ return s[13] != '\0';]])],
+ [gl_cv_func_strndup_works=yes],
+ [gl_cv_func_strndup_works=no],
+ [
+changequote(,)dnl
+ case $host_os in
+ aix | aix[3-6]*) gl_cv_func_strndup_works="guessing no";;
+ *) gl_cv_func_strndup_works="guessing yes";;
+ esac
+changequote([,])dnl
+ ])])
+ case $gl_cv_func_strndup_works in
+ *no) REPLACE_STRNDUP=1 ;;
+ esac
+ else
+ HAVE_STRNDUP=0
+ fi