get more heavy-handed with compilation requirements

build.zig

@@ -78,6 +78,10 @@ pub fn build(b: *std.Build) void {
 }
 
 pub fn configureBuild(b: *std.Build, cs: *std.Build.Step.Compile, function_name: []const u8) !void {
+    if (cs.rootModuleTarget().os.tag != .wasi) {
+        std.log.err("Error: Cloudflare builds require compilation with -Dtarget=wasm32-wasi", .{});
+        return error.WasiCompilationRequired;
+    }
     const script = @embedFile("index.js");
     const wasm_name = try std.fmt.allocPrint(b.allocator, "{s}.wasm", .{cs.name});
     const deploy_cmd = CloudflareDeployStep.create(