Preserve one byte for end of string character in form_update_line()

Bug-Debian: https://github.com/tats/w3m/issues/82
cf. https://github.com/tats/w3m/issues/68#issuecomment-266214643

1 files changed, 1 insertions, 1 deletions

diff --git a/form.c b/form.c
index 0dfbaa8..fdad786 100644
--- a/form.c
+++ b/form.c
@@ -319,7 +319,7 @@ form_update_line(Line *line, char **str, int spos, int epos, int width,
     }
     pos += width - w;
 
-    len = line->len + pos + spos - epos;
+    len = line->len + pos + spos - epos + 1;
     buf = New_N(char, len);
     prop = New_N(Lineprop, len);
     bcopy((void *)line->lineBuf, (void *)buf, spos * sizeof(char));