Strange Makefile build error on tikv-jemalloc-sys 0.7.1

[orlp]

We now get the following build error while trying to build tikv-jemalloc-sys:

--- stderr
  make[2]: *** No rule to make target 's'.  Stop.

  thread 'main' (47826) panicked at /home/ubuntu/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tikv-jemalloc-sys-0.7.1+5.3.1-0-g81034ce1f1373e37dc865038e1bc8eeecf559ce8/build.rs:441:9:
  command did not execute successfully: cd "/home/ubuntu/polars/target/debug/build/tikv-jemalloc-sys-241a2b995cdbb770/out/build" && MAKEFLAGS="-j --jobserver-fds=8,9 --jobserver-auth=8,9 s" "make"
  expected success, got: exit status: 2
  note: run with RUST_BACKTRACE=1 environment variable to display a backtrace

I have no idea the extra s ends up in

MAKEFLAGS="-j --jobserver-fds=8,9 --jobserver-auth=8,9 s"

I checked and as far as I can see we're not setting MAKEFLAGS anywhere.

[orlp]

The problem lies here:

jemallocator/jemalloc-sys/build.rs

Line 405 in 0e91291

format!("{makeflags} {orig_makeflags}")

This is not how you merge MAKEFLAGS. Make is very strange in that it will parse and mangle the command line options, turning single-character flags into a block at the start. Take a look at this Makefile:

foo:
    echo $(MAKEFLAGS)

If I now run:

$ make -w -j 8 -k foo
wk --jobserver-fds=3,4 -j

Note how it combined the -w and -k options into just a string wk at the start?

However if you now naively concatenate this with something which specified -k, you'd get:

ws --jobserver-fds=3,4 -j k

Now this might work with some versions of Make, but not GNU Make:

$ MAKEFLAGS='-j16 s' make
make: *** No rule to make target 's'.  Stop.
$ make --v
GNU Make 4.4.1
Built for x86_64-pc-linux-gnu
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.