cmd/5g, cmd/6g, cmd/8g: simplify for loop in bitmap generation

Lucio De Re reports that the more complex
loop miscompiles on Plan 9.

R=ken2
CC=golang-dev
https://codereview.appspot.com/13602043
sort: fix Example_sortMultiKeys

Old example referenced global var from multiSorter.Sort and ignored it's argument.
Changed one of example calls to actually pass slice to sort.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/13551044

Committer: Russ Cox <rsc@golang.org>
archive/tar: fix a case where USTAR-split is not working correctly.

For some long filenames the USTAR-split code does not work
correctly. It is wrongly assumed that the path would not be too long,
but it is.

The user visible result was that a filename was split, but it still
caused an error.

The cause was a wrongly calculated nlen. In addition I noticed that
at this place it is also seems necessary to check if the prefix will
fit in the 155 chars available for the prefix.

R=dsymonds, rsc
CC=golang-dev
https://codereview.appspot.com/13300046

Committer: Russ Cox <rsc@golang.org>