This relates to esp-rs/esp-wifi-sys#16

In https://github.com/bjoernQ/xtensa-rust-variadics-problem-repo I have some very simple code to reproduce the problem.

What I do there

• Rust calls function in C
• That function calls a function in Rust with variadics

On RISCV it works as expected and outputs

42 "TAG" "FORMAT"
1 = 1
2 = 2
3 = 3
4 = 4
5 = 5
6 = 6
7 = 7
8 = 8
9 = 9

On ESP32 it outputs

42 "TAG" "FORMAT"
1 = 1061160316
2 = 1
3 = 2
4 = 3
5 = 2148373693
6 = 1073594208
7 = 1074266112
8 = 1073414160
9 = 4