add XInputSetState export in proxy loader, fixing certain steam emus

Author: dankmeme01

loader/launcher/windows/proxyLoader.cpp

@@ -6,6 +6,7 @@
 
 struct XINPUT_STATE;
 struct XINPUT_CAPABILITIES;
+struct XINPUT_VIBRATION;
 
 constexpr static auto MAX_PATH_CHARS = 32768u;
 
@@ -41,6 +42,17 @@ extern "C" DWORD XInputGetState(DWORD dwUserIndex, XINPUT_STATE *pState) {
     return ERROR_DEVICE_NOT_CONNECTED;
 }
 
+#pragma comment(linker, "/export:XInputSetState,@3")
+extern "C" DWORD XInputSetState(DWORD dwUserIndex, XINPUT_VIBRATION* pVibration) {
+    static auto fp = getFP("XInputSetState");
+    if (fp) {
+        using FPType = decltype(&XInputSetState);
+        return reinterpret_cast<FPType>(fp)(dwUserIndex, pVibration);
+    }
+
+    return ERROR_DEVICE_NOT_CONNECTED;
+}
+
 #pragma comment(linker, "/export:XInputGetCapabilities,@4")
 extern "C" DWORD XInputGetCapabilities(DWORD dwUserIndex, DWORD dwFlags, XINPUT_CAPABILITIES *pCapabilities) {
     static auto fp = getFP("XInputGetCapabilities");