Fix missing include path to jni_md.h on some systems

Issue introduced in 5003b0d.

Author: robinlinden

cpp/CMakeLists.txt

@@ -43,6 +43,9 @@ find_package(JNI)
 if(JAVA_INCLUDE_PATH)
   include_directories(${JAVA_INCLUDE_PATH})
 endif()
+if(JAVA_INCLUDE_PATH2)
+  include_directories(${JAVA_INCLUDE_PATH2})
+endif()
 
 include_directories("src")
 include_directories(${CMAKE_BINARY_DIR})