plugins: fix inclusion of user-mode APIs

plugins: fix inclusion of user-mode APIs

In 903e870f24 (plugins/api: split out binary path/start/end/entry
code) we didn't actually enable the building of the new plugin helper.
However this was missed because only contrib plugins like drcov
actually used the helpers.

With that fixed we discover we also need some more includes to be able
to extract the relevant data from TaskState.

Fixes: 903e870f24 (plugins/api: split out binary path/start/end/entry code)
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3014
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-ID: <20250710104531.3099313-6-alex.bennee@linaro.org>