Added gradle and cmake project

@@ -189,11 +189,11 @@
  * such as with mouse messages.
  */
 #define LO_INT(l)           ((int)(short)(l))
 #define HI_INT(l)           ((int)(short)(((DWORD)(l) >> 16) & 0xFFFF))
 
-extern JavaVM *jvm;
+extern "C" JavaVM *jvm;
 
 // Platform encoding is Unicode (UTF-16), re-define JNU_ functions
 // to proper JNI functions.
 #define JNU_NewStringPlatform(env, x) env->NewString(reinterpret_cast<const jchar*>(x), static_cast<jsize>(_tcslen(x)))
 #define JNU_GetStringPlatformChars(env, x, y) reinterpret_cast<LPCWSTR>(env->GetStringChars(x, y))