My environment are Windows10, Gnu and busybox.

--- stdout
cargo:rerun-if-env-changed=LIBZ_SYS_STATIC
cargo:rerun-if-changed=build.rs
TARGET = Some("x86_64-pc-windows-gnu")
OPT_LEVEL = Some("3")
HOST = Some("x86_64-pc-windows-gnu")
CC_x86_64-pc-windows-gnu = None
CC_x86_64_pc_windows_gnu = None
HOST_CC = None
CC = None
CFLAGS_x86_64-pc-windows-gnu = None
CFLAGS_x86_64_pc_windows_gnu = None
HOST_CFLAGS = None
CFLAGS = None
CRATE_CC_NO_DEFAULTS = None
DEBUG = Some("false")
CARGO_CFG_TARGET_FEATURE = Some("fxsr,sse,sse2")

cargo:warning=BusyBox v1.32.0-FRP-3329-gcf0fa4d13 (2020-01-09 09:35:27 GMT) multi-call binary
cargo:warning=
cargo:warning=Usage: ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES
cargo:warning=
cargo:warning=Extract or list FILES from an ar archive
cargo:warning=
cargo:warning= -o Preserve original dates
cargo:warning= -p Extract to stdout
cargo:warning= -t List
cargo:warning= -x Extract
cargo:warning= -v Verbose
cargo:warning=F:\scoop\apps\busybox\current\busybox.exe: unknown option -- s
exit code: 1

--- stderr

The fellow is output of ar:

ar crs
F:\scoop\apps\busybox\current\busybox.exe: unknown option -- s
BusyBox v1.32.0-FRP-3329-gcf0fa4d13 (2020-01-09 09:35:27 GMT) multi-call binary

Usage: ar [-o] [-v] [-p] [-t] [-x] ARCHIVE FILES

Extract or list FILES from an ar archive

    -o      Preserve original dates
    -p      Extract to stdout
    -t      List
    -x      Extract
    -v      Verbose

The 's' option is invalid in windows10.