sys-apps/man-db: Sync with Gentoo

It's from Gentoo commit acb3e08ca43b0704723eb2347fcdc2c754dc7733.

Author: Flatcar Buildbot

sdk_container/src/third_party/portage-stable/sys-apps/man-db/man-db-2.12.0.ebuild

@@ -13,7 +13,7 @@ if [[ ${PV} == *9999 ]] ; then
 else
 	# TODO: Change tarballs to gitlab too...?
 	SRC_URI="mirror://nongnu/${PN}/${P}.tar.xz"
-	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~x64-solaris"
+	KEYWORDS="~alpha amd64 arm arm64 hppa ~ia64 ~loong ~m68k ~mips ppc ppc64 ~riscv ~s390 sparc x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~x64-solaris"
 fi
 
 LICENSE="GPL-3"