Xtensa support

[Matheus Catarino via D.gnu]

I've recently seen support for different target architectures on 
https://explore.dgnu.org .
What is the status of Xtensa and xtensa-gnu support? Does it 
support both xtensa ABIs (call0 and windowed)?

Currently there is a need to fork espressif/LLVM when using ldc2. 
Is there a need to fork espressif crosstool-ng?