Writing plugins in C can be sometimes tedious, especially when using Glib to
keep track of execution state. We can directly use the same C API but write our
plugin in C++, benefiting from its great standard library offering strings,
smart pointers, data structures and synchronization mechanisms.

It's common for downstream QEMU forks to provide C++ for plugins, like this:
- https://github.com/panda-re/panda/tree/dev/panda/plugins
- https://github.com/FlorentRevest/DejaView/tree/main/src/qemu_plugin

Hopefully this will help more people to use upstream QEMU, and as a benefit, get
their contribution back and help to develop plugins ecosystem upstream directly.

This series first cleans up build system for plugins, factorizing details
between contrib/plugins and tests/tcg/plugins folders.
Then, we perform codebase cleanups to fix conflicts between existing headers
and C++ headers.
After that, we can update the C++ standard used by QEMU, to benefit fully
from latest updates of the language.
Finally, we define an empty C++ plugin, making sure we can keep track of
possible regression in qemu-plugin header.

Note: This series is *not* a trojan horse to bring C++ in QEMU
codebase, nor to define an alternative C++ API for plugins. It's just enabling
more users to get the most out of existing C plugin API.

CI: https://gitlab.com/pbo-linaro/qemu/-/pipelines/2242427013

v4
--

rebase on top of master (new conflict with ./scripts/clean-includes)

v3
--

- fix indentation in patch 2

v2
--

- drop coroutine.h rename patch as it's not needed
- drop ctype.h rename patch, and move qemu-plugin.h to include/plugins
- fix mem.c to not depend on other QEMU headers

Pierrick Bouvier (11):
  plugins: move win32_linker.c file to plugins directory
  plugins: factorize plugin dependencies and library details
  plugins: use complete filename for defining plugins sources
  plugins: define plugin API symbols as extern "C" when compiling in C++
  tests/tcg/plugins/mem.c: remove dependency on qemu headers
  plugins: move qemu-plugin.h to include/plugins/
  meson: fix supported compiler arguments in other languages than C
  meson: enable cpp (optionally) for plugins
  qga/vss-win32: fix clang warning with C++20
  meson: update C++ standard to C++23
  contrib/plugins: add empty cpp plugin

 docs/devel/tcg-plugins.rst                  |   4 +-
 meson.build                                 |  26 +++--
 include/{qemu => plugins}/qemu-plugin.h     |  11 +-
 include/qemu/plugin.h                       |   2 +-
 plugins/core.c                              |   2 +-
 {contrib/plugins => plugins}/win32_linker.c |   0
 tests/tcg/plugins/mem.c                     |  59 ++++------
 contrib/plugins/cpp.cpp                     | 119 ++++++++++++++++++++
 contrib/plugins/meson.build                 |  25 ++--
 plugins/meson.build                         |  17 ++-
 qga/vss-win32/requester.cpp                 |   6 +-
 tests/tcg/plugins/meson.build               |  18 +--
 12 files changed, 203 insertions(+), 86 deletions(-)
 rename include/{qemu => plugins}/qemu-plugin.h (99%)
 rename {contrib/plugins => plugins}/win32_linker.c (100%)
 create mode 100644 contrib/plugins/cpp.cpp

-- 
2.47.3