This patch works around the problem that causes invalid memory access error
on Cygwin.

--- history.c.orig	2011-05-17 00:08:59.297965400 +0900
+++ history.c	2011-05-17 00:10:00.941791700 +0900
@@ -575,6 +575,7 @@
  * If there is no more line in the file, false is returned. */
 bool read_line(FILE *restrict f, xwcsbuf_T *restrict buf)
 {
+    wb_ensuremax(buf, LINE_MAX);
     while (fgetws(&buf->contents[buf->length],
 		buf->maxlength - buf->length + 1, f)) {
 	size_t len = wcslen(&buf->contents[buf->length]);