net: Always set WSA_FLAG_OVERLAPPED when creating Windows sockets. Rework send and receive logic to use overlapped I/O.

build-web: Remove the now-redundant supports_recv logic

lib/build-web/main.js

@@ -6,7 +6,7 @@ const domSummary = {
   stepCount: document.getElementById("summaryStepCount"),
   status: document.getElementById("summaryStatus"),
 };
-let domButtonRebuild = document.getElementById("buttonRebuild");
+const domButtonRebuild = document.getElementById("buttonRebuild");
 const domStepList = document.getElementById("stepList");
 let domSteps = [];
 
@@ -114,13 +114,7 @@ function hello(
   steps_len,
   build_status,
   time_report,
-  supports_recv,
 ) {
-  if (!supports_recv && domButtonRebuild) {
-    domButtonRebuild.remove();
-    domButtonRebuild = null;
-  }
-
   domSummary.stepCount.textContent = steps_len;
   updateBuildStatus(build_status);
   setConnectionStatus("", false);
@@ -167,15 +161,11 @@ function updateBuildStatus(s) {
   if (active) {
     domSummary.status.classList.add("status-running");
     domSummary.status.classList.remove("status-idle");
-    if (domButtonRebuild) {
-      domButtonRebuild.disabled = true;
-    }
+    domButtonRebuild.disabled = true;
   } else {
     domSummary.status.classList.remove("status-running");
     domSummary.status.classList.add("status-idle");
-    if (domButtonRebuild) {
-      domButtonRebuild.disabled = false;
-    }
+    domButtonRebuild.disabled = false;
   }
   if (reset_time_reports) {
     // Grey out and collapse all the time reports

lib/build-web/main.zig

@@ -30,7 +30,6 @@ const js = struct {
         steps_len: u32,
         status: abi.BuildStatus,
         time_report: bool,
-        supports_recv: bool,
     ) void;
     extern "core" fn updateBuildStatus(status: abi.BuildStatus) void;
     extern "core" fn updateStepStatus(step_idx: u32) void;
@@ -161,7 +160,7 @@ fn helloMessage(msg_bytes: []align(4) u8) Allocator.Error!void {
     step_list = steps;
     step_list_data = duped_step_name_data;
 
-    js.hello(step_list.len, hdr.status, hdr.flags.time_report, hdr.flags.supports_recv);
+    js.hello(step_list.len, hdr.status, hdr.flags.time_report);
 }
 fn statusUpdateMessage(msg_bytes: []u8) Allocator.Error!void {
     if (msg_bytes.len < @sizeOf(abi.StatusUpdate)) @panic("malformed StatusUpdate message");