If you enable "Option -> Show Debug Info" and click a link, the program
terminates with the following error:
*** buffer overflow detected ***: terminated
The buffer overflow is caused by the following line:
strcat(data, "$");
The buffer needs one more byte to accommodate the additional character.
Fixes: c4f7398bee9c ("kconfig: qconf: make debug links work again")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>