[context] Build error with context-impl

From: Tim Haines (thaines.astro_at_[hidden])
Date: 2024-10-07 17:02:16

git -c advice.detachedHead=false clone --branch develop --single-branch
--depth 1 https://github.com/boostorg/boost.git
git -c advice.detachedHead=false submodule update --init --recursive
./bootstrap.sh --with-toolset=gcc --with-libraries=context
./b2 -d+2 --debug-configuration --debug-building --debug-generator headers
context-impl=fcontext toolset=gcc cxxstd=20

notice: found boost-build.jam at  /boostorg/boost-build.jam
notice: loading B2 from  /boostorg/tools/build/src/build-system.jam
notice: Searching <redacted> for site-config configuration file
'site-config.jam'.
notice: Configuration file 'site-config.jam' not found in <redacted>.
notice: Searching <redacted> for user-config configuration file
'user-config.jam'.
notice: Configuration file 'user-config.jam' not found in <redacted>.
notice: Searching '.' for project-config configuration file
'project-config.jam'.
notice: Loading project-config configuration file 'project-config.jam' from
'.'.
notice: will use 'g++' for gcc, condition <toolset>gcc-11
notice: using gcc libraries :: <toolset>gcc-11 :: /usr/bin /usr/lib
/usr/lib32 /usr/lib64
notice: using gcc archiver :: <toolset>gcc-11 :: /usr/bin/ar
warning: toolset gcc initialization: can not find tool windres
warning: initialized from project-config.jam:12
notice: using rc compiler :: <toolset>gcc-11 :: /usr/bin/as
/boostorg/tools/build/src/build/feature.jam:327: in validate-feature from
module feature
error: unknown feature "<context-impl>"
 /boostorg/tools/build/src/build/feature.jam:361: in expand-subfeatures-aux
from module feature
 /boostorg/tools/build/src/build/feature.jam:422: in
feature.expand-subfeatures from module feature
 /boostorg/tools/build/src/build/build-request.jam:20: in
apply-to-property-set from module build-request
(builtin):-1: in sequence.transform from module sequence
 /boostorg/tools/build/src/build/build-request.jam:32: in
build-request.expand-no-defaults from module build-request
 /boostorg/tools/build/src/build-system.jam:778: in module scope from
module build-system

The feature is present:

grep -A5 -n "feature.feature context-impl" libs/context/build/Jamfile.v2
52:feature.feature context-impl
53-    : fcontext
54-      ucontext
55-      winfib
56-    : propagated
57-      composite

I'm not familiar with the Jam DSL, so I'm not sure how to debug this
further. Any advice is very welcome.

Thanks.
- Tim