dev-libs/md4c: keyword 0.5.2 for ~loong

Untested, blindly adding (timeout) because dropping ~loong from all of
dev-qt/*-6.9.2 just because of this would be a pain and do not really
want to delay the bump either.

Thankfully md4c is rather simple, and sounds unlikely to be broken.
Not to mention that qtbase used to use a bundled copy of md4c and it
worked fine on ~loong.

Closes: https://bugs.gentoo.org/957680
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

dev-libs/md4c/md4c-0.5.2.ebuild

@@ -18,7 +18,7 @@ if [[ ${PV} == 9999 ]]; then
 else
 	SRC_URI="https://github.com/mity/md4c/archive/refs/tags/release-${PV}.tar.gz -> ${P}.tar.gz"
 	S="${WORKDIR}/md4c-release-${PV}"
-	KEYWORDS="amd64 ~arm ~arm64 ~hppa ~ppc ~ppc64 ~riscv ~x86"
+	KEYWORDS="amd64 ~arm ~arm64 ~hppa ~loong ~ppc ~ppc64 ~riscv ~x86"
 fi
 
 LICENSE="MIT test? ( CC-BY-SA-4.0 )"