fix(cli.rs): check default arch at runtime, closes #3067 (#3078)

.changes/cli.rs-fix-windows-x86.md

@@ -0,0 +1,5 @@
+---
+"cli.rs": patch
+---
+
+Fix `build` command when executed on a 32-bit Windows machine when pulling from the `binary-releases` repo.

tooling/cli.rs/src/build.rs

@@ -174,22 +174,17 @@ pub fn command(options: Options) -> Result<()> {
     // move merge modules to the out dir so the bundler can load it
     #[cfg(windows)]
     {
-      let arch = if let Some(t) = &options.target {
-        if t.starts_with("x86_64") {
-          "x86_64"
-        } else if t.starts_with('i') {
-          "x86"
-        } else if t.starts_with("arm") {
-          "arm"
-        } else if t.starts_with("aarch64") {
-          "aarch64"
-        } else {
-          panic!("Unexpected target triple {}", t)
-        }
-      } else if cfg!(target_arch = "x86") {
+      let target = options.target.clone().unwrap_or_else(|| std::env::consts::ARCH.into());
+      let arch = if target.starts_with("x86_64") {
+        "x86_64"
+      } else if target.starts_with('i') || target.starts_with("x86") {
         "x86"
+      } else if target.starts_with("arm") {
+        "arm"
+      } else if target.starts_with("aarch64") {
+        "aarch64"
       } else {
-        "x86_64"
+        panic!("Unexpected target architecture {}", target.split("_").next().unwrap())
       };
       let (filename, vcruntime_msm) = if arch == "x86" {
         let _ = std::fs::remove_file(out_dir.join("Microsoft_VC142_CRT_x64.msm"));