procfs: load config files from binfmt.d into /proc/sys/fs/binfmt_misc/register

This is a KISS version.  Let's see where we go from here in terms of
complexity.  Maybe nowhere!

X-Gentoo-Bug: 382723
X-Gentoo-Bug-URL: https://bugs.gentoo.org/382723
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

init.d/procfs.in

@@ -54,7 +54,18 @@ start()
 			ebegin "Mounting misc binary format filesystem"
 			mount -t binfmt_misc -o nodev,noexec,nosuid \
 				binfmt_misc /proc/sys/fs/binfmt_misc
-			eend $?
+			if eend $? ; then
+				local fmts
+				ebegin "Loading custom binary format handlers"
+				fmts=$(grep -hsv -e '^[#;]' -e '^[[:space:]]*$' \
+					/run/binfmt.d/*.conf \
+					"/etc"/binfmt.d/*.conf \
+					""/usr/lib/binfmt.d/*.conf)
+				if [ -n "${fmts}" ]; then
+					echo "${fmts}" > /proc/sys/fs/binfmt_misc/register
+				fi
+				eend $?
+			fi
 		fi
 	fi