call-process-internal is racy

There is a window between the start-process-internal and the set-process-sentinel where, depending on scheduling and signals whims, the process can finish. Then the sentinel is never called, and everything craps up. It seems to be rare enough in normal use (even if afaik the linux scheduler would make it more probable than expected though) but it makes tracing completely impossible. I have no clue on how to fix it. My lisp skills are inexistant. OG, trying to fix the package install on 21.5[1] [1] The results of the gunzip -c |tar xvf - appear in the *Package Output* buffer after the start-process-internal but dissapear somewhere before the end of the function.