Bundled clippy is built with incorrect sysroot

[o01eg]

See rust-lang/rust-clippy#2874

Clippy is compiled with SYSROOT environment variable is "" while correct value should be "/usr"

config.toml:

[llvm]
optimize = true
release-debuginfo = false
assertions = false
targets = "X86;Mips;NVPTX;BPF;AArch64"
[build]
build = "x86_64-unknown-linux-gnu"
host = ["x86_64-unknown-linux-gnu"]
target = ["x86_64-unknown-linux-gnu"]
docs = false
submodules = false
python = "python2.7"
locked-deps = true
vendor = false
verbose = 2
sanitizers = false
extended = true
tools = ["clippy",]
[install]
prefix = "/usr"
libdir = "lib64/rust-9999"
docdir = "share/doc/rust-9999"
mandir = "share/rust-9999/man"
[rust]
optimize = true
debuginfo = false
debug-assertions = true # false
jemalloc = true
default-linker = "x86_64-pc-linux-gnu-gcc"
rpath = false
ignore-git = false
lld = false
llvm-tools = true
[target.x86_64-unknown-linux-gnu]
cc = "x86_64-pc-linux-gnu-gcc"
cxx = "x86_64-pc-linux-gnu-g++"
linker = "x86_64-pc-linux-gnu-gcc"
ar = "x86_64-pc-linux-gnu-ar"

OS: Gentoo Linux AMD64

[flip1995]

This should've been fixed here: rust-lang/rust-clippy@f5db351

It is also tested by Clippy's CI, that clippy-driver and rustc always print the same sysroot.

[o01eg]

Currently clippy works without patches so I suppose this issues was fixed before.