regression in make 4.3 with makefile from stdin

[Natanael Copa]

Hi,

I believe there is a regression in make 4.3. To reproduce:


$ make -v
GNU Make 4.3
Built for x86_64-alpine-linux-musl
Copyright (C) 1988-2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://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.
$ cat Makefile 
all:
        @echo \$(CC)
$ make -sf Makefile 
cc
$ cat Makefile  | env -i make -sf -
make: echo: No such file or directory
make: *** [/tmp/GmOCOMgl:2: all] Error 127



Problem was found in the configure script of mandoc (mdocml).

  CC=`printf "all:\\n\\t@echo \\\$(CC)\\n" | env -i make -sf -`

https://cvsweb.bsd.lv/mandoc/configure?rev=1.71&content-type=text/x-cvsweb-markup


Downstream bug report:
https://gitlab.alpinelinux.org/alpine/aports/issues/11163

Thanks!

-nc