Add support for modular build structure.

[grafikrobot]

This is part of the effort to make the Boost libraries "modular" for build and consumption. See https://lists.boost.org/Archives/boost/2024/01/255704.php and https://github.com/grafikrobot/boost-b2-modular/blob/b2-modular/README.adoc for more information.

This PR depends on the following other PRs being merged to both develop and master branches of the respective repos:

• Add support for modular build structure. boost#854

[pdimov]

Unnecessary CI changes. Also, it's a bit odd for build/Jamfile to be deleted.

[grafikrobot]

Unnecessary CI changes.

Undone. But a bunch of other CI changes to make things actually work.

Also, it's a bit odd for build/Jamfile to be deleted.

True. But it essentially did nothing anyway.

[sdarwin]

Circleci boost builds are failing, it seems to correspond with this quickbook PR merge today.

maybe not important, but there was a switch from "cxxstd-0x-iso release" to "cxxstd-11-iso debug".

log file line 113, before:

[1] gcc-13
[2] gcc-13/release/x86_64/cxxstd-0x-iso/link-static/visibility-hidden
# /root/project> 'b2' '--debug-configuration' '-j3' '-q' '-d0' '--build-dir=/root/build' '--distdir=/root/build/dist' 'tools/quickbook' '' execution time 60.259230852127075 seconds

log file line 113, after:

[1] gcc-13
[2] gcc-13/debug/x86_64/cxxstd-11-iso/link-static/visibility-hidden
# /root/project> 'b2' '--debug-configuration' '-j3' '-q' '-d0' '--build-dir=/root/build' '--distdir=/root/build/dist' 'tools/quickbook' '' execution time 49.32090091705322 seconds

[pdimov]

From the Circle log, it appears like building the Quickbook documentation itself hangs, for some reason. But I can't reproduce this here.

[sdarwin]

Add back release to the quickbook target

This may apply to b2 or quickbook , but the log output line 113 still says debug instead of release.

gcc-13/debug/x86_64/cxxstd-11-iso/link-static/visibility-hidden

[pdimov]

Looks like debug is being built, yes. But there's nothing in the log because of -d0. Which script was that, again?

[pdimov]

OK, let's see how that would go. boostorg/release-tools@fd465df

[pdimov]

I can confirm that building tools/quickbook installs the debug build.

C:\boost-git\develop\tools\quickbook>b2 .
Performing configuration checks

...

[1] msvc-14.3
[2] msvc-14.3/debug/x86_64/cxxstd-11-iso/link-static/python-3.9/threadapi-win32/threading-multi/visibility-hidden
...patience...
...patience...
...found 5407 targets...
...updating 1 target...
common.copy C:\boost-git\develop\dist\bin\quickbook.exe
..\..\bin.v2\tools\quickbook\src\msvc-14.3\debug\x86_64\cxxstd-11-iso\link-static\threading-multi\quickbook.exe
        1 file(s) copied.

...updated 1 target...

[pdimov]

I have no idea how default-build is supposed to work in this case, what's inherited from what and how <cxxstd>11 and <variant>release are combined. But in either case, this change fea2283 seems to fix it for me locally, that is, building tools/quickbook now installs the release build.

An easier change would have been to just put <variant>release into the project default-build, and maybe that's the right one. I went with the above because it's closer to what the original did.