- Update bash 5.1 to patch level 12
* Add official patch bash51-009
The bash malloc implementation of malloc_usable_size() does not follow the
specification. This can cause library functions that use it to overwrite
memory bounds checking.
* Add official patch bash51-010
If `wait -n' is interrupted by a trapped signal other than SIGINT, it does
not completely clean up state, and that can prevent subsequent calls to
`wait -n' from working correctly.
* Add official patch bash51-011
When reading a compound assignment, and running it through the parser to
split it into words, we need to save and restore any alias we're currently
expanding.
* Add official patch bash51-012
There is a possible race condition that arises when a child process receives
a signal trapped by the parent before it can reset the signal dispositions.
The child process is not supposed to trap the signal in this circumstance.

- Using package bash-sh instead of the update-alternative
mechanism.