Invalid `SHELL` in `Makefile` for AIX builds?

Bug report

Bug description:

When trying to build CPython on AIX, the make steps fails immediately with the following error message:

$ ./configure
[...]
$ make       
/bin/sh -e: not found

make: 1254-004 The error code from the last command is 1.


Stop.

AIX make(1) interprets whatever is assigned to the SHELL variable as a file path to the shell. It thus tries to use a shell named "/bin/sh -e":

execve("/bin/sh -e", 0x0000000110004D28, 0x0FFFFFFFFFFFFB90) Err#2  ENOENT

The -e was added by #100220, however I wonder if this is the right approach.

Going by POSIX I think -e should be the default unless it is explicitly disabled:

The execution line shall then be executed by a shell as if it were passed as the argument to the system() interface, except that if errors are not being ignored then the shell -e option shall also be in effect. If errors are being ignored for the command (as a result of the -i option, a '-' command prefix, or a .IGNORE special target), the shell -e option shall not be in effect.

I assume the -e was added for GNU make, which does not set -e unless it is set to POSIX-conforming mode (GNU make: Choosing the shell).

If the Makefile is defined to be a POSIX Makefile, wouldn't it be better to define .POSIX: in the makefile?

Quick test with GNU make:

$ cat Makefile
.POSIX:

SHELL = /bin/sh

test:
	false; echo after false
$ make --version
GNU Make 4.4.1
Built for powerpc64le-unknown-linux-musl
Copyright (C) 1988-2023 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
$ make test
false; echo after false
make: *** [Makefile:4: test] Error 1

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

Linked PRs

• gh-149022

Issue này trỏ đến Makefile và ghi chú rằng -e được thêm bởi #100220; hãy bắt đầu từ đó và so sánh cách AIX make xử lý SHELL với hành vi POSIX được trích dẫn. Tái hiện lỗi trên AIX hoặc kiểm tra phần công việc được liên kết gh-149022; việc hoàn tất được xác định khi Makefile không còn truyền đường dẫn shell không hợp lệ cho AIX make.