libfplll fails to build in parallel on Cygwin

[jpflori]

On my installation of Cywgin (on 64 bits Windows 7), building libfplll fails because make complains there is no rule to build fplll if I use MAKE=make -j4".
Indeed there is one for fplll$(EXEEXT), but no for fplll and $(EXEEXT) is non empty on Cygwin.
Nonetheless, if the file fplll.exe exists, then "make fplll" will happily tell you that its up to date and go on with its job.

This does not happen with a sequential build.

Use the spkg at
http://boxen.math.washington.edu/home/jpflori/libfplll-3.0.12.p3.spkg

And by the way the libfplll we ship is old and the problem is not present in the most recent version.
See #12835.
So I won't report this upstream.

Upstream: None of the above - read trac for reasoning.

CC: @kcrisman @dimpase

Component: porting: Cygwin

Keywords: libfplll spkg cygwin

Author: Jean-Pierre Flori

Reviewer: Karl-Dieter Crisman

Merged: sage-5.6.rc0

Issue created by migration from https://trac.sagemath.org/ticket/13804

[jpflori]

comment:1

Or maybe Cywgin make used to automagically translate targets to add .exe extension and does not anymore.

[jpflori]

comment:2

Groumpf, I got it to install by not using a parallel build.

[kcrisman]

comment:3

Yeah, I've never seen this because my machine is certainly always with one thread. I guess I never even thought to try it in parallel, but as it's XP I'm sure that wouldn't be very useful in any case.

[jpflori]

Spkg diff, for review only.

[jpflori]

Author: Jean-Pierre Flori

[jpflori]

comment:4

Attachment: libfplll-3.0.12.p3.diff.gz

[kcrisman]

comment:5

Brief look at diff seems okay, and this installed fine on XP with passed (self, SAGE_CHECK=yes) tests. I obviously can't check whether this actually works in terms of multiple threads, though this is the right command to disable parallel make, and is only on Cygwin, so we should probably let it go through.

[kcrisman]

Reviewer: Karl-Dieter Crisman

[kcrisman]

comment:6

Same result on Mac and sage.math, and after ./sage -b passes the sage/libs/fplll tests as well. Let's get this in.

[jdemeyer]

Merged: sage-5.6.rc0