build: install Rust toolchain for Slint

thirdparty/rust/xmake.lua

@@ -0,0 +1,35 @@
+package("rust")
+    set_kind("toolchain")
+    set_homepage("https://rust-lang.org")
+    set_description("Rust is a general-purpose programming language emphasizing performance, type safety, and concurrency.")
+
+    add_versions("1.92.0", "")
+
+    add_deps("ca-certificates", {host = true, private = true})
+    add_deps("rustup", {host = true, private = true, system = false})
+
+    on_install(function(package)
+        import("core.tools.rustc.target_triple")
+
+        local host_target = assert(target_triple(package:plat(), package:arch()),
+            "failed to determine the Rust host target triple")
+        local version = package:version():shortstr()
+        local toolchain_name = version .. "-" .. host_target
+        local rustup_home = assert(os.getenv("RUSTUP_HOME"), "cannot find rustup home")
+
+        os.vrunv("rustup", {"install", "--no-self-update", toolchain_name})
+        os.vmv(path.join(rustup_home, "toolchains", toolchain_name, "*"), package:installdir())
+
+        -- Keep the Xmake-managed toolchain isolated from rustup after installation.
+        os.vrm(path.join(rustup_home, "toolchains", toolchain_name))
+        os.vrm(path.join(rustup_home, "update-hashes", toolchain_name))
+
+        package:addenv("RC", "bin/rustc" .. (is_host("windows") and ".exe" or ""))
+        package:mark_as_pathenv("RC")
+    end)
+
+    on_test(function(package)
+        os.vrun("cargo --version")
+        os.vrun("rustc --version")
+    end)
+package_end()

thirdparty/slint/xmake.lua

@@ -10,6 +10,7 @@ package("slint")
     add_configs("shared", {description = "Build the Slint runtime as a shared library", default = true, type = "boolean", readonly = true})
 
     add_deps("cmake")
+    add_deps("rust 1.92.0", {host = true, private = true, system = false})
 
     on_load(function(package)
         package:add("includedirs", "include/slint")

thirdparty/xmake.lua

@@ -1 +1 @@
-includes("cpp-httplib", "slint")
+includes("cpp-httplib", "rust", "slint")