* [java] extending the library loader to use both OS and CPU architecture.
* Simplifying create_jni.py's architecture detection.
* Tidying up the architecture detection in create_jni.py
The old NativeLibLoader had a short-circuit load path which modified
java.library.path and attempted to load the xgboost library from outside
the jar first, falling back to loading the library from inside the jar.
This path is a no-op every time when using XGBoost outside of it's
source tree. Additionally it triggers an illegal reflective access
warning in the module system in 9, 10, and 11.
On Java 12 the ClassLoader fields are not accessible via reflection
(separately from the illegal reflective acces warning), and so it fails
in a way that isn't caught by the code which falls back to loading the
library from inside the jar.
This commit removes that code path and always loads the xgboost library
from inside the jar file as it's a valid technique across multiple JVM
implementations and works with all versions of Java.
* Changes for Mingw64 compilation to ensure long is a consistent size.
Mainly impacts the Java API which would not compile, but there may be
silent errors on Windows with large datasets before this patch (as long
is 32-bits when compiled with mingw64 even in 64-bit mode).
* Adding ifdefs to ensure it still compiles on MacOS
* Makefile and create_jni.bat changes for Windows.
* Switching XGDMatrixCreateFromCSREx JNI call to use size_t cast
* Fixing lint error, adding profile switching to jvm-packages build to make create-jni.bat get called, adding myself to Contributors.Md
Adam Pocock