Working with libR-sys requires files like these

config.toml

[env]
LIBCLANG_PATH = "C:/Users/angus/scoop/apps/llvm/current/lib"
RUST_BACKTRACE = "full"
LIBRSYS_BINDINGS_OUTPUT_PATH = "mybindings"
R_HOME = "C:/Users/angus/scoop/apps/R/current"

[build]
target-dir = "target"
# target = "x86_64-pc-windows-msvc"
# target = "x86_64-pc-windows-gnu"

[term]
quiet = false
verbose = true

# [target.x86_64-pc-windows-gnu]
# linker = "x86_64-w64-mingw32.static.posix-gcc.exe"

# [target.x86_64-pc-windows-msvc]
# linker = "rust-lld"

settings.json

{
    "rust-analyzer.checkOnSave": false,
    "rust-analyzer.cargo.features": [
        "use-bindgen"
    ],
    "rust-analyzer.runnableEnv": {
        "LIBCLANG_PATH": "C:/Users/angus/scoop/apps/llvm/current/lib",
        "R_HOME": "C:/Users/angus/scoop/apps/R/current",
        "PATH": "${env:R_HOME}/bin/x64;${env:RTOOLS40_HOME}/x86_64-w64-mingw32.static.posix/bin;${env:RTOOLS40_HOME}/usr/bin;${env:PATH}"
        // "LIBCLANG_PATH": "C:/Users/angus/scoop/apps/llvm/current/lib"
    },
    "rust-analyzer.cargo.extraEnv": {
        "LIBCLANG_PATH": "C:/Users/angus/scoop/apps/llvm/current/lib",
        // "R_HOME": "C:/Program Files/R/R-4.2.2",
        "R_HOME": "C:/Users/angus/scoop/apps/R/current",
        // "RTOOLS40_HOME": "C:/Users/angus/scoop/apps/rtools/current",
        "PATH": "${env:R_HOME}/bin/x64;${env:RTOOLS40_HOME}/x86_64-w64-mingw32.static.posix/bin;${env:RTOOLS40_HOME}/usr/bin;${env:PATH}"
    },
    "terminal.integrated.env.windows": {
        "LIBCLANG_PATH": "C:/Users/angus/scoop/apps/llvm/current/lib",
        // "R_HOME": "C:/Program Files/R/R-4.2.2",
        "R_HOME": "C:/Users/angus/scoop/apps/R/current",
        // "RTOOLS40_HOME": "C:/Users/angus/scoop/apps/rtools/current",
        "PATH": "${env:R_HOME}/bin/x64;${env:RTOOLS40_HOME}/x86_64-w64-mingw32.static.posix/bin;${env:RTOOLS40_HOME}/usr/bin;${env:PATH}"
    }
}