games-board/gnuchess: BDEPEND on help2man

Bit annoying as it uses `missing` so we don't notice if it's actually
*absent*, (=> nobody filed a bug until now / noticed the missing dep) but
if it's present-but-broken (e.g. needs a rebuild for Locale-gettext) then
it'll be used and bomb out like in the bug as Portage didn't know gnuchess
was using it so wasn't forced to schedule it after help2man was rebuilt.

Closes: https://bugs.gentoo.org/950973
Signed-off-by: Sam James <sam@gentoo.org>

games-board/gnuchess/gnuchess-6.2.9-r1.ebuild

@@ -1,4 +1,4 @@
-# Copyright 1999-2023 Gentoo Authors
+# Copyright 1999-2025 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 EAPI=8
@@ -13,6 +13,8 @@ LICENSE="GPL-3"
 SLOT="0"
 KEYWORDS="amd64 ~arm arm64 ~loong ppc64 ~riscv x86"
 
+BDEPEND="sys-apps/help2man"
+
 PATCHES=(
 	"${FILESDIR}"/${PN}-6.2.9-c++17.patch
 	"${FILESDIR}"/${PN}-6.2.9-configure-quoting.patch