Yet Another Shell

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Handle E_ASYNC in exec_commands

The exec_one_command function now takes the finally_exit parameter
instead of a exec_T.

Rename exec_simple_command -> invoke_simple_command

Rewrite exec_commands

Template of exec_one_command

Create branch exec

More tests on redirection affecting environment

Test setting new trap in trap

Rewrite signal handling tests (#40851)

Analyze with CodeQL

configure: Create *.d files safely

The previous implementation (recursively calling function) was not
safe when there was some symbolic link to a directory

Ignore SIGINT/SIGQUIT/SIGTSTP after phantomizing traps

The `phantomize_traps' function was overwriting the results of the
`ignore_sigquit_and_sigint' and `ignore_sigtstp' functions. This commit
reorders the function calls.

Allow trapping SIGINT/SIGQUIT in asynchronous list (#40767)

Refactor reset_special_handler

Refactor sig.c

* original_sigmask is renamed to official_sigmask
* ignored_signals is renamed to officially_ignored_signals
* originally_defaulted_signals and originally_ignored_signals are added

Test initially ignored signal on child process

Test setting new trap for USR1 & CHLD in async list

Don't assume independent subshell

Some shells do not always create a child process for executing a
subshell. To ensure a signal is sent from another process, avoid sending
from a subshell.

More tests on signal handling in asynchronous list

Correct comment for open_redirections

Don't undo redirections on subshell (#40766)

More test on redirected trap built-in

More tests on expansion error in bracket command

Treat special backslashes in pathname patterns (#40755)

Correct escaping in quote removal in double bracket command

Unescaping the result of quote_removal(..., ES_QUOTED_HARD) is not the
same as quote_removal(..., ES_NONE).

Correct escaping in quote removal in expand_single_with_glob

Unescaping the result of quote_removal(..., ES_QUOTED_HARD) is not the
same as quote_removal(..., ES_NONE).

Correct escaping in quote removal in globbing

Unescaping the result of quote_removal(..., ES_QUOTED_HARD) is not the
same as quote_removal(..., ES_NONE).

No empty field removal in expand_word

This affects the result of "${{@}}" where $# = 0.

Remove fixed parameter from expand_single_with_glob

Remove fixed parameters from expand_word

Use expand_single_cc in expand_single