Adapt everything in BT5 to new capnhook API

This includes:
- Renaming of functions (iohook_invoke_next)
- Slight interface changes (com_proxy_wrap, iohook_push_handler)
- De-duplicate stuff from utils (iobuf, hr)

src/main/sdvxhook/acio.c

@@ -51,7 +51,7 @@ ac_io_bus_dispatch_irp(struct irp *irp)
     log_assert(irp != NULL);
 
     if (!ac_io_emu_match_irp(&ac_io_emu, irp)) {
-        return irp_invoke_next(irp);
+        return iohook_invoke_next(irp);
     }
 
     for (;;) {

src/main/sdvxhook/dllmain.c

@@ -22,11 +22,6 @@
 static bool my_dll_entry_init(char *sidcode, struct property_node *config);
 static bool my_dll_entry_main(void);
 
-static const irp_handler_t sdvxhook_handlers[] = {
-    ac_io_bus_dispatch_irp,
-    lcd_dispatch_irp,
-};
-
 static bool my_dll_entry_init(char *sidcode, struct property_node *config)
 {
     bool ok;
@@ -123,7 +118,10 @@ BOOL WINAPI DllMain(HMODULE self, DWORD reason, void *ctx)
     args_free(argc, argv);
 
     app_hook_init(my_dll_entry_init, my_dll_entry_main);
-    iohook_init(sdvxhook_handlers, lengthof(sdvxhook_handlers));
+
+    iohook_push_handler(ac_io_bus_dispatch_irp);
+    iohook_push_handler(lcd_dispatch_irp);
+
     rs232_hook_init();
 
     gfx_init();

src/main/sdvxhook/gfx.c

@@ -91,7 +91,7 @@ static HRESULT STDCALL my_CreateDevice(
     D3DPRESENT_PARAMETERS *pp,
     IDirect3DDevice9 **pdev)
 {
-    IDirect3D9 *real = COM_PROXY_UNWRAP(self);
+    IDirect3D9 *real = com_proxy_downcast(self)->real;
     HRESULT hr;
 
     log_misc("IDirect3D9::CreateDevice hook hit");
@@ -117,11 +117,18 @@ static IDirect3D9 *STDCALL my_Direct3DCreate9(UINT sdk_ver)
     IDirect3D9 *api;
     IDirect3D9Vtbl *api_vtbl;
     struct com_proxy *api_proxy;
+    HRESULT hr;
 
     log_info("Direct3DCreate9 hook hit");
 
     api = real_Direct3DCreate9(sdk_ver);
-    api_proxy = com_proxy_wrap(api, sizeof(*api->lpVtbl));
+    
+    hr = com_proxy_wrap(&api_proxy, api, sizeof(*api->lpVtbl));
+    
+    if (hr != S_OK) {
+        log_fatal("Wrapping com proxy failed: %08lx", hr);
+    }
+
     api_vtbl = api_proxy->vptr;
 
     api_vtbl->CreateDevice = my_CreateDevice;

src/main/sdvxhook/lcd.c

@@ -31,7 +31,13 @@ void lcd_init(void)
 {
     log_assert(lcd_fd == NULL);
 
-    lcd_fd = iohook_open_dummy_fd();
+    HRESULT hr;
+    
+    hr = iohook_open_nul_fd(&lcd_fd);
+
+    if (hr != S_OK) {
+        log_fatal("Opening nul fd failed: %08lx", hr);
+    }
 }
 
 void lcd_fini(void)
@@ -49,7 +55,7 @@ lcd_dispatch_irp(struct irp *irp)
     log_assert(irp != NULL);
 
     if (irp->op != IRP_OP_OPEN && irp->fd != lcd_fd) {
-        return irp_invoke_next(irp);
+        return iohook_invoke_next(irp);
     }
 
     switch (irp->op) {
@@ -73,7 +79,7 @@ static HRESULT lcd_open(struct irp *irp)
     log_assert(irp != NULL);
 
     if (!wstr_eq(irp->open_filename, L"COM1")) {
-        return irp_invoke_next(irp);
+        return iohook_invoke_next(irp);
     }
 
     irp->fd = lcd_fd;