My custom toolchain not found!

[corpserot]

-- toolchains/llvm_mingw.lua
toolchain("llvm_mingw")
    -- APACHE 2.0 license
    -- Copyright (C) 2015-present, TBOOX Open Source Group.
    -- With modifications

    set_kind("standalone")
    set_description("LLVM-based MinGW Clang toolchain")
    set_runtimes("stdc++_static", "stdc++_shared")

    on_check(function(toolchain)
        import("core.project.config")
        import("detect.sdks.find_mingw")
        local mingw
        for _, package in ipairs(toolchain:packages()) do
            local installdir = package:installdir()
            if installdir and os.isdir(installdir) then
                mingw = find_mingw(installdir, {verbose = true, cross = toolchain:cross()})
                if mingw then
                    break
                end
            end
        end
        if not mingw then
            mingw = find_mingw(toolchain:config("mingw") or config.get("mingw"), {verbose = true, bindir = toolchain:bindir(), cross = toolchain:cross()})
        end
        if mingw then
            toolchain:config_set("mingw", mingw.sdkdir)
            toolchain:config_set("cross", mingw.cross)
            toolchain:config_set("bindir", mingw.bindir)
            toolchain:configs_save()
            return true
        end
    end)

    on_load(function(toolchain)
        import("core.project.config")

        -- get cross
        local cross
        if toolchain:is_arch("x86_64", "x64") then
            cross = "x86_64-w64-mingw32-"
        elseif toolchain:is_arch("i386", "x86", "i686") then
            cross = "i686-w64-mingw32-"
        elseif toolchain:is_arch("arm64", "aarch64") then
            cross = "aarch64-w64-mingw32-"
        elseif toolchain:is_arch("armv7", "arm.*") then
            cross = "armv7-w64-mingw32-"
        else
            cross = toolchain:cross() or ""
        end

        -- add bin search library for loading some dependent .dll files windows
        local bindir = toolchain:bindir()
        if bindir and is_host("windows") then
            toolchain:add("runenvs", "PATH", bindir)
        end

        toolchain:add("toolset", "cc", cross .. "clang")
        toolchain:add("toolset", "cxx", cross .. "clang++", cross .. "clang")
        -- toolchain:add("toolset", "cpp", cross .. "gcc -E")
        toolchain:add("toolset", "as", cross .. "clang")
        toolchain:add("toolset", "ld", cross .. "clang++", cross .. "clang")
        toolchain:add("toolset", "sh", cross .. "clang++", cross .. "clang")
        toolchain:add("toolset", "ar", cross .. "llvm-ar")
        toolchain:add("toolset", "strip", cross .. "strip")
        toolchain:add("toolset", "ranlib", cross .. "llvm-ranlib")
        toolchain:add("toolset", "objcopy", cross .. "objcopy")
        toolchain:add("toolset", "mrc", cross .. "windres")
        toolchain:add("toolset", "dlltool", cross .. "dlltool")
        toolchain:add("toolset", "mm", cross .. "clang")
        toolchain:add("toolset", "mxx", cross .. "clang", cross .. "clang++")

        -- init flags for architecture
        local archflags = nil
        local arch = toolchain:arch()
        if arch == "x86_64" then archflags = "-m64"
        elseif arch == "i386" then archflags = "-m32"
        end
        if archflags then
            toolchain:add("cxflags", archflags)
            toolchain:add("asflags", archflags)
            toolchain:add("ldflags", archflags)
            toolchain:add("shflags", archflags)
        end
    end)

[corpserot]

to solve this: inside my xmake.lua file, put includes("toolchain/llvm_mingw.lua") so xmake actually reads the script. next, use --plat cross --toolchain=llvm_mingw✔ instead of -p llvm_mingw❌