makepkg: avoid reporting bogus install size on btrfs

delayed allocation hoses us here and causes erroenous install sizes to
be reported. Add a short sleep to allow the transaction to be committed
to the filesystem and the stat buffers to be updated.

This is apparently a "feature", as per to some of the denizens of #btrfs
on freenode.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>

scripts/makepkg.sh.in

@@ -1120,6 +1120,12 @@ write_pkginfo() {
 	else
 		local packager="Unknown Packager"
 	fi
+
+	# btrfs's delayed allocation causes the stat buffers from the kernel to "lie"
+	# to us momentarily and report 0 blocks allocated (which is how du calculates
+	# size). Sleeping for a second here is about the dirtiest thing possible,
+	# but avoids reporting entirely bogus install sizes.
+	sleep 1
 	local size="$(@DUPATH@ -sk)"
 	size="$(( ${size%%[^0-9]*} * 1024 ))"