In commit 30fd43d7f3b8716054eb9867c835aadc423f652c, unescape was
simplified significantly, but the new version failed to NULL terminate
the resulting string.
This causes bad behavior in various utilities, for example tr:
Broken:
$ echo b2 | tr '\142' '\143'
c3
Fixed:
$ echo b2 | tr '\142' '\143'
c2
This bug breaks libtool's usage of tr, causing gcc to fail to build with
sbase.