U-Boot CI error, unable to reproduce locally

[Marek Behun]

Hello Tom,

I seem to run into an error on Azure's CI for U-Boot that I cannot
reproduce locally.

It concerns my LTO work https://github.com/u-boot/u-boot/pull/57

The test
  u-boot.u-boot (test.py xilinx_zynq_virt)
is failing with this log
https://dev.azure.com/u-boot/a1096300-2999-4ec4-a21a-4c22075e3771/_apis/build/builds/1936/logs/283

The error seems to be
  make[3]: *** read jobs pipe: No such file or directory.  Stop.
  lto-wrapper: fatal error: make returned 2 exit status
as if make's jobserver died, or something.

But when I build with buildman on my local machine, everything is OK.

How should I proceed?

Marek