ci-cygwin.yml: Multi-stage build

[mkoeppe]

The GitHub workflow for cygwin does not fit into the 6-hour time limit.
We do a multi-stage build, saving and loading local/ to/from build artifacts.

Depends on #29417
Depends on #29392

CC: @dimpase @embray @slel @jpflori @tscrim @vbraun @kcrisman

Component: porting: Cygwin

Author: Matthias Koeppe

Branch/Commit: 27ddea3

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/29403

[mkoeppe]

Branch: u/mkoeppe/ci_cygwin_yml__multi_stage_build

[sagetrac-git]

Commit: 79bee2f

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

79bee2f

ci-cygwin.yml: Remove sage-spkg -y -o

[sagetrac-git]

Changed commit from 79bee2f to cef0d73

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. Last 10 new commits:

cd0a0ec	handle symlinks
5a387d0	Use winsymlinks:native
122f972	Full targets
424d86e	prepare the final logs artifact
f646274	store local/var/tmp/sage/build in logs artifact
6924328	stage 1
97d3f86	touch installation records to get same mtime
5939bc7	Upload log artifact first
59d20e0	stage 4
cef0d73	more stages

[mkoeppe]

comment:4

Sample run https://github.com/mkoeppe/sage/actions/runs/63708828

[mkoeppe]

Dependencies: #29397

[mkoeppe]

comment:6

Something is still triggering rebuilds of targets that have been built in a previous stage.

[dimpase]

comment:7

I'd suspect it's the toolchain crud.

[mkoeppe]

Changed dependencies from #29397 to none

[mkoeppe]

comment:9

I'm running one test with MAKE="make --debug=verbose" to see what's happening there

[sagetrac-git]

Changed commit from cef0d73 to de50cf8

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

de50cf8

better touch

[mkoeppe]

Author: Matthias Koeppe

[mkoeppe]

comment:13

This works pretty well now.