diff -ru z/ckucmd.c k/ckucmd.c
--- z/ckucmd.c	2004-01-07 10:04:04.000000000 -0800
+++ k/ckucmd.c	2019-01-01 15:52:44.798864262 -0800
@@ -7103,7 +7103,7 @@
 
 /* Here we must look inside the stdin buffer - highly platform dependent */
 
-#ifdef _IO_file_flags			/* Linux */
+#ifdef _IO_EOF_SEEN			/* Linux */
     x = (int) ((stdin->_IO_read_end) - (stdin->_IO_read_ptr));
     debug(F101,"cmdconchk _IO_file_flags","",x);
 #else  /* _IO_file_flags */