Re: Regression on Cygwin: Problems with parallel make in 4.4

[Ken Brown]

On 2/19/2023 9:29 AM, Paul Smith wrote:
> I will change the default setting of the jobserver to use "pipe" on
> Cygwin, at least for now.

Parallel make is still not working reliably.  I've just discovered that 
my TeX Live build logs have several occurrences of the following warning:

  jobserver unavailable: using -j1.  Add '+' to parent make rule.

This has been going on since I first started using 4.4.0.90 with the 
jobserver style set to "pipe".  It *only* occurs when the jobserver uses 
a pipe.  Two others in the Cygwin community are reporting the same thing 
when they build projects using cmake (with Unix Makefiles and make 
4.4.0.91).

I don't know if this is Cygwin-specific, since other platforms (except 
GNU/Hurd) are using fifos.  So the "pipe" jobserver style might not have 
gotten a lot of testing since the switch to fifos was made.

I guess the first step in tracking this down is for people working on 
other platforms to see if they can reproduce the problem when they set 
the jobserver style to "pipe".

Unfortunately, I don't have a simple reproduction recipe.  I myself have 
seen it when building TeX Live, as I've said, and also when building 
doxygen (which uses cmake with Unix Makefiles).  The other Cygwin users 
who have reported the problem (both CC'd) haven't yet said what cmake 
projects they were building.

Ken