library interfaces: remove dependency on config.h

[davidpanderson]

We need to be able to compile with libboinc and libboinc_api without needing config.h.

To do this: avoid having .h files include other .h files
(in particular, avoid chains of includes that lead to str_replace.h,
which is what needs config.h).

Fixes #6271

[Copilot]

Pull Request Overview

This PR removes unnecessary dependencies on config.h by reducing header interdependencies and replacing includes with forward declarations where possible.

• Updated test files to include missing headers for error numbers and parsing.
• Replaced direct inclusion of specific headers in library files with forward declarations.
• Modified MIOFILE from a class to a struct in header files to avoid including config.h unnecessarily.

Reviewed Changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/unit-tests/lib/test_str_util.cpp	Added include for error_numbers.h to support testing functionality
tests/unit-tests/lib/test_parse.cpp	Added include for parse.h to support testing functionality
lib/win_util.cpp	Added include for error_numbers.h to resolve dependency
lib/util.cpp	Added include for str_replace.h in implementation file
lib/str_util.h	Removed include of str_replace.h to break dependency chain
lib/proxy_info.h	Replaced a class declaration with a forward declaration for MIOFILE
lib/opencl_boinc.h	Replaced header includes with forward declarations to eliminate dependency chains
lib/miofile.h	Changed MIOFILE from a class to a struct to simplify interface declarations
lib/coproc.h	Removed parse.h include while adding forward declarations
lib/common_defs.h	Replaced includes with forward declarations to reduce dependency on config.h
lib/app_ipc.cpp	Added include for str_replace.h as needed in the implementation
client/hostinfo_linux.cpp	Adjusted include order to support new dependencies
client/client_msgs.h	Updated function signature by removing redundant 'class' keyword

Comments suppressed due to low confidence (2)

lib/miofile.h:42

• Changing MIOFILE from a class to a struct alters the default access level for its members; please confirm that all member variables and functions are intended to be public.

-class MIOFILE {

client/client_msgs.h:47

• [nitpick] Removing the redundant 'class' keyword in the function parameter improves clarity; please ensure the corresponding implementation is updated accordingly.

void write(int seqno, class MIOFILE&, bool translatable);

[AenBleidd]

I keep this open for a while to make a full test with building libboinc independently and linking to the test code.
Should take me a couple of days to do that.

[davidpanderson]

BTW, the test is: compile an app that uses libboinc_api and libboinc
(and therefore includes api/boinc_api.h and e.g. lib/util.h)
without config.h anywhere.
I did this using samples/example_app/ (by renaming boinc/config.h)
on Win and Linux and it worked.

[AenBleidd]

That's similar to what I plan to do, with the only different that in my case I want to have these builds separated, and the app should not have physical access to the 'config.h' file to be sure that there is no other hidden place.
And I want to make it another automated test to prevent such cases in the future.
Anyway, thank you for the fix, @davidpanderson 👍