Complete solution for installing the generated *.pc files

[mkoeppe]

Follow up from #29082.

This ticket makes sure that installed pc files in SAGE_LOCAL are uninstalled correctly when the installation changes, via the staging/uninstalling mechanism extended to script packages by #29386.

• Code in build/make/Makefile.in is removed in favor of creating one or several new type=script packages, whose spkg-install does the installation to SAGE_LOCAL.

Depends on #29082
Depends on #29386

CC: @dimpase @jhpalmieri

Component: build

Branch/Commit: u/mkoeppe/system_blas_facade @ b493a32

Issue created by migration from https://trac.sagemath.org/ticket/29387

[mkoeppe]

Branch: u/mkoeppe/system_blas_facade

[mkoeppe]

Commit: b493a32

[mkoeppe]

Dependencies: #29082, #29386

[mkoeppe]

comment:2

The branch on the ticket is the old branch from #29082. Needs work.

---

Last 10 new commits:

dbb9860	build/pkgs/texlive/spkg-install: Fix up path
8b1d5ca	trac 29287: rewording documentation
057a66b	Make pyopenssl a pip package
8f6323e	src/sage/env.py: Fix up doctest on starting sage without SAGE_* variables
0919086	trac 29287: doc fixes
6781790	Move all BLAS PC file installation logic to new script package sage_sage_system_blas_facade
30d3b82	build/pkgs/openblas/spkg-configure.m4: Separate library names by spaces
b68595e	Change type
7fd5e31	fixup
b493a32	install sage_system_blas_facade

[mkoeppe]

comment:3

pushing these forward to 9.2

[mkoeppe]

comment:5

Setting new milestone based on a cursory review of ticket status, priority, and last modification date.