JNI: don't implement a signature for 'long' C++ type

On Android, `long` has the width of the system, while `jlong` is always
64 bit. If we support `long` as a signature type equivalent to `jlong`,
then it becomes possible to write code that fails to compile, or in the
worst case crashes at runtime, on a 32bit system.

Instead, support quint64, which is always the same size as jlong.

Change-Id: I60432ec7411e697b5f6e1f153216ceee0af7e0f1
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

src/corelib/kernel/qjnitypes_impl.h

@@ -221,7 +221,7 @@ struct Traits {
             return CTString("I");
         } else if constexpr (std::is_same_v<T, jlong>) {
             return CTString("J");
-        } else if constexpr (std::is_same_v<T, long>) {
+        } else if constexpr (std::is_same_v<T, quint64>) {
             return CTString("J");
         } else if constexpr (std::is_same_v<T, jfloat>) {
             return CTString("F");

src/plugins/platforms/android/qandroidplatformclipboard.cpp

@@ -28,7 +28,7 @@ void QAndroidPlatformClipboard::onClipboardDataChanged(JNIEnv *env, jobject obj,
 QAndroidPlatformClipboard::QAndroidPlatformClipboard()
 {
     m_clipboardManager = QtClipboardManager::construct(QtAndroidPrivate::context(),
-                                                       reinterpret_cast<long>(this));
+                                                       reinterpret_cast<jlong>(this));
 }
 
 QAndroidPlatformClipboard::~QAndroidPlatformClipboard()

tests/auto/corelib/kernel/qjnitypes/tst_qjnitypes.cpp

@@ -137,7 +137,7 @@ enum class IntEnum : int {};
 enum class UnsignedEnum : unsigned {};
 enum class Int8Enum : int8_t {};
 enum class ShortEnum : short {};
-enum class LongEnum : long {};
+enum class LongEnum : quint64 {};
 enum class JIntEnum : jint {};
 
 static_assert(QtJniTypes::Traits<UnscopedEnum>::signature() == "I");
@@ -153,7 +153,7 @@ void tst_QJniTypes::initTestCase()
 
 }
 
-static bool nativeFunction(JNIEnv *, jclass, int, jstring, long)
+static bool nativeFunction(JNIEnv *, jclass, int, jstring, quint64)
 {
     return true;
 }