Reported by Paul Eggert in
<https://lists.gnu.org/archive/html/bug-gnulib/2024-07/msg00292.html>.
* pygnulib/GLInfo.py (GLInfo.usage): Document
--extract-usability-in-testdir option.
* pygnulib/GLModuleSystem.py (GLModule.section_label_pattern): Recognize
Usable-in-testdir section.
(GLModule.getUsabilityInTestdir): New function.
* pygnulib/GLTestDir.py (GLTestDir.execute): Invoke it to filter out
modules to avoid. Warn if such a module was specified.
* pygnulib/main.py (main): Add support for
--extract-usability-in-testdir. Provide an error message for error 24.
* pygnulib/GLError.py: Likewise.
* modules/config-h (Usable-in-testdir): New section.
* modules/lib-ignore (Usable-in-testdir): New section.
* modules/mountlist (Usable-in-testdir): New section.
* modules/non-recursive-gnulib-prefix-hack (Usable-in-testdir): New
section.
* modules/timevar (Usable-in-testdir): New section.
(Files): Remove lib/timevar.def.
This reverts commit df6f91c as the evaluation of the passed shell
variable happens at the wrong time in the references generated by
m4/non-recursive-gnulib-prefix-hack.m4
Revert to the hardcoded "lib/".
* build-aux/prefix-gnulib-mk: Copied from coreutils, derived from
the file that originated in Bison.
* m4/non-recursive-gnulib-prefix-hack.m4: Likewise, this code is
largely copied from a snippet that resided in bison's configure.ac.
* modules/non-recursive-gnulib-prefix-hack: New file.
* MODULES.html.sh (Support for maintaining and releasing projects):
Add it.
