version of package sage_conf for relocatable binary distributions

[mkoeppe]

This version of sage_conf is for making a relocatable binary distribution of the Sage distribution using the method proposed in #31076, using SAGE_ROOT=/var/tmp/sage-... and a symlink.

[mkoeppe]

Last 10 new commits:

​61f6ba6	Makefile: Add top-level targets build-local, build-venv
​b8b8a06	Put both versions of sage_conf sources into subdirectories of SAGE_ROOT/src/pkgs/
​ff7f110	build/pkgs/sage_conf/install-requires.txt: New
​072b522	Determine SAGE_ROOT from sage version and python version
​fa4cbfa	Run .homebrew-build-env and set 'make -j...' automatically
​fa9485c	Remove sage_bootstrap.build (not needed for this ticket)
​7bdc524	build/pkgs/sage_conf/src: Restore symlink
​76d151e	build/bin/write-dockerfile.sh: Fix up docker tests
​1a8cadc	src/pkgs/sage_conf-pypi/setup.cfg: Under version control, not gitignored
​a62e1e9	src/pkgs/sage_conf-binary: New

[mkoeppe]

To select a version of sage_conf, we may want to add a configure option --with-sage-conf=...; or just activate it using --enable-relocatable

[mkoeppe]

Replying to mkoeppe:

To select a version of sage_conf, we may want to add a configure option --with-sage-conf=...; or just activate it using --enable-relocatable ... or --with-relocation-link=/var/tmp/....

[git]

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

​70cc566

WIP

[mkoeppe]

Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review of ticket status, priority, and last modification date.