Fix TCC Windows crash: replace FnDecl compound literals with memdup

The large compound literal for `&ast.FnDecl{...*node, generic_names: ...}`
generated ~1KB of stack-allocated struct initialization with 50+ field
assignments including bitfields, which TCC on Windows x64 miscompiles
causing a runtime crash (invalid memory access at checker/fn.v call_expr).

Replace with memdup + direct field write to avoid the problematic compound
literal. Also fix cube.js.v formatting for MSVC CI.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: medvednikov

examples/js_dom_cube/cube.js.v

@@ -336,7 +336,8 @@ fn animate(mut state State, time f64) {
 	state.gl.uniformMatrix4fv(state.mmatrix, JS.Boolean(false), state.mo_matrix.to_number_array())
 
 	state.gl.bindBuffer(dom.gl_element_array_buffer(), state.index_buffer)
-	state.gl.drawElements(dom.gl_triangles(), JS.Number(indices.len), dom.gl_unsigned_short(), JS.Number(0))
+	state.gl.drawElements(dom.gl_triangles(), JS.Number(indices.len), dom.gl_unsigned_short(),
+		JS.Number(0))
 
 	dom.window().requestAnimationFrame(fn [mut state] (time JS.Number) {
 		animate(mut state, f64(time))

vlib/v/checker/fn.v

@@ -745,9 +745,10 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 	if c.table.cur_concrete_types.len > 0
 		&& effective_generic_names.len == c.table.cur_concrete_types.len
 		&& node.generic_names != effective_generic_names {
-		effective_cur_fn = &ast.FnDecl{
-			...*node
-			generic_names: effective_generic_names.clone()
+		unsafe {
+			effective_cur_fn = &ast.FnDecl(memdup(node, sizeof(ast.FnDecl)))
+			mut p := &[]string(&effective_cur_fn.generic_names)
+			*p = effective_generic_names.clone()
 		}
 	}
 	c.table.cur_fn = effective_cur_fn
@@ -3446,9 +3447,10 @@ fn (mut c Checker) post_process_generic_fns() ! {
 						}
 					}
 					if effective_generic_names.len == concrete_types.len {
-						concrete_fn = &ast.FnDecl{
-							...*concrete_fn
-							generic_names: effective_generic_names
+						unsafe {
+							concrete_fn = &ast.FnDecl(memdup(concrete_fn, sizeof(ast.FnDecl)))
+							mut p := &[]string(&concrete_fn.generic_names)
+							*p = effective_generic_names
 						}
 					}
 				}