gh-124928: Emscripten node support: Clean up old node <= 16 flags (#124929)

Clean up configure flags for old node versions

These flags are only needed for node <= 16. Node 16 has been end of life since
October of 2023.

Author: hoodmane

Misc/NEWS.d/next/Build/2024-10-04-17-29-23.gh-issue-124928.FsGffe.rst

@@ -0,0 +1 @@
+Emscripten builds now require node >= 18.

Tools/wasm/emscripten/node_pre.js

@@ -0,0 +1,9 @@
+// If process is undefined, we're not running in the node runtime let it go I
+// guess?
+if (typeof process !== "undefined") {
+    const nodeVersion = Number(process.versions.node.split('.',1)[0]);
+    if (nodeVersion < 18) {
+        process.stderr.write(`Node version must be >= 18, got version ${process.version}\n`);
+        process.exit(1);
+    }
+}

configure

@@ -1622,34 +1622,6 @@ then
     [Emscripten/node*], [
       AC_PATH_TOOL([NODE], [node], [node])
       HOSTRUNNER="$NODE"
-      # bigint for ctypes c_longlong, c_longdouble
-      # no longer available in Node 16
-      AC_CACHE_CHECK([for node --experimental-wasm-bigint], [ac_cv_tool_node_wasm_bigint], [
-        if $NODE -v --experimental-wasm-bigint > /dev/null 2>&1; then
-          ac_cv_tool_node_wasm_bigint=yes
-        else
-          ac_cv_tool_node_wasm_bigint=no
-        fi
-      ])
-      AS_VAR_IF([ac_cv_tool_node_wasm_bigint], [yes], [
-        AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-bigint"])
-      ])
-
-      AS_VAR_IF([enable_wasm_pthreads], [yes], [
-        AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-threads"])
-        # no longer available in Node 16
-        AC_CACHE_CHECK([for node --experimental-wasm-bulk-memory], [ac_cv_tool_node_wasm_bulk_memory], [
-          if $NODE -v --experimental-wasm-bulk-memory > /dev/null 2>&1; then
-            ac_cv_tool_node_wasm_bulk_memory=yes
-          else
-            ac_cv_tool_node_wasm_bulk_memory=no
-          fi
-        ])
-        AS_VAR_IF([ac_cv_tool_node_wasm_bulk_memory], [yes], [
-          AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-bulk-memory"])
-        ])
-      ])
-
       AS_VAR_IF([host_cpu], [wasm64], [AS_VAR_APPEND([HOSTRUNNER], [" --experimental-wasm-memory64"])])
     ],
     dnl TODO: support other WASI runtimes
@@ -2424,6 +2396,7 @@ AS_CASE([$ac_sys_system],
       ],
       [node*], [
         AS_VAR_IF([ac_sys_emscripten_target], [node-debug], [wasm_debug=yes])
+        AS_VAR_APPEND([LDFLAGS_NODIST], [" --pre-js=\$(srcdir)/Tools/wasm/emscripten/node_pre.js"])
         AS_VAR_APPEND([LDFLAGS_NODIST], [" -sALLOW_MEMORY_GROWTH -sNODERAWFS"])
         AS_VAR_APPEND([LINKFORSHARED], [" -sEXIT_RUNTIME"])
         WASM_LINKFORSHARED_DEBUG="-gseparate-dwarf --emit-symbol-map"