build/make/Makefile.in: Fix SAGE_CHECK logic, conditionalize sagetex dependencies on SAGE_CHECK

[mkoeppe]

(from #30315)

As previously observed in #30324, the SAGE_CHECK logic implemented in #30118 and improved in #29766 still does not work correctly with dependencies conditionalized on SAGE_CHECK.

We fix it (again...?!) by moving the computation of the SAGE_CHECK_... variables earlier, before the dependencies are evaluated.

To test it, we conditionalize sagetex dependencies on SAGE_CHECK:

$ make sagetex-clean jmol-clean
$ make sagetex                    # should NOT build jmol
$ make sagetex-clean
$ SAGE_CHECK=yes make sagetex     # now it builds jmol

CC: @jhpalmieri @dimpase @kliem @orlitzky

Component: build

Keywords: sd111

Author: Matthias Koeppe

Branch/Commit: 1f714c1

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/31020

[mkoeppe]

Branch: u/mkoeppe/build_make_makefile_in__fix_sage_check_logic__conditionalize_sagetex_dependencies_on_sage_check

[mkoeppe]

Commit: 1f714c1

[mkoeppe]

New commits:

0ed256c	build/make/Makefile.in: Compute SAGE_CHECK_... earlier, before evaluating dependencies
1f714c1	build/pkgs/sagetex/dependencies: Conditionalize order-only deps on SAGE_CHECK_sagetex

[mkoeppe]

Changed keywords from none to sd111

[dimpase]

comment:4

lgtm

[dimpase]

Reviewer: Dima Pasechnik

[mkoeppe]

comment:5

Thanks!

[vbraun]

Changed branch from u/mkoeppe/build_make_makefile_in__fix_sage_check_logic__conditionalize_sagetex_dependencies_on_sage_check to 1f714c1