--- /dev/null
+# serial 1
+
+# From Paul Eggert.
+
+# Some versions of BeOS define mbstate_t to be an incomplete type,
+# so you can't declare an object of that type.
+# Check for this incompatibility with Standard C.
+
+AC_DEFUN(AC_MBSTATE_T_OBJECT,
+ [AC_CACHE_CHECK([for mbstate_t object type], ac_cv_type_mbstate_t_object,
+ [AC_TRY_COMPILE([#include <wchar.h>],
+ [mbstate_t x; return sizeof x;],
+ ac_cv_type_mbstate_t_object=yes,
+ ac_cv_type_mbstate_t_object=no)])
+ if test $ac_cv_type_mbstate_t_object = yes; then
+ AC_DEFINE(HAVE_MBSTATE_T_OBJECT, 1,
+ [Define if mbstate_t is an object type.])
+ fi])