Make public headers safe for consumers building with -Werror

[bmehta001]

Summary

Consumers that embed this SDK and compile their own code with -Wall -Wextra -Werror (e.g. ONNX Runtime / Foundry Local, which consume the SDK via add_subdirectory) were broken by warnings emitted from inside the SDK's public headers. This PR makes the public headers safe to include under strict, warning-as-error builds.

Two complementary changes:

1. Mark the exported public include dir as SYSTEM (primary fix)

lib/CMakeLists.txt now uses target_include_directories(mat SYSTEM PUBLIC ...). find_package consumers already treat an imported target's includes as system headers (so their warnings are suppressed); the SYSTEM keyword extends the same courtesy to add_subdirectory/FetchContent consumers. This covers every consumer and every warning flag — including diagnostics that have no clean C++11 header-level fix (-Wpedantic variadic-macro warnings from the LM_SAFE_CALL family, -Wsign-conversion in the Variant union).

2. Header hygiene (defense in depth)

Also fixes the actual warnings, which helps non-CMake consumers (Bazel/Buck/Make copying the headers) and CMake consumers that set NO_SYSTEM_FROM_IMPORTED:

• ctmacros.hpp — UNREFERENCED_PARAMETER(...) expanded to nothing on gcc/clang (there was a TODO acknowledging this), so the parameter stayed unused and tripped -Wunused-parameter. It now casts the argument to void, eliminating 5 -Wunused-parameter warnings across NullObjects.hpp and LogManagerProvider.hpp.
• ISemanticContext.hpp — the assert(!"message") idiom triggers clang's -Wstring-conversion; switched to the canonical assert(false && "message") (2 sites).

Impact on a consumer including the main public headers

Consumer flags	Before	After (headers only)	After (with SYSTEM)
-Wall -Wextra	5	0	0
+ -Wpedantic	22	17	0
+ -Wshadow -Wconversion (clang)	9	2	0

Validation

• Header re-measure (gcc 13 + clang 18, including LogManager.hpp, EventProperties.hpp, CorrelationVector.hpp, PayloadDecoder.hpp, Variant.hpp, LogManagerProvider.hpp): -Wall -Wextra drops 5 → 0.
• SYSTEM propagation: configured the SDK via add_subdirectory and confirmed mat's INTERFACE_SYSTEM_INCLUDE_DIRECTORIES contains the public include dir.
• End-to-end: a consumer treating the public dir as -isystem compiles clean under -Wall -Wextra -Wpedantic -Wshadow -Wconversion -Werror on both gcc and clang; and a minimal add_subdirectory reproduction confirmed a consumer's -Werror fails without SYSTEM and passes with it.
• No SDK regression: the SDK's own top-level legacy build (libmat.so) compiles cleanly with the UNREFERENCED_PARAMETER change across all 75 call sites.

Public API and ABI are unchanged (UNREFERENCED_PARAMETER is a no-side-effect discard; the assert change is textual). The default build is otherwise unaffected.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

[Copilot]

Pull request overview

This PR aims to ensure the SDK’s public headers can be included by downstream consumers that build with strict warning-as-error flags (e.g. -Wall -Wextra -Werror), especially when consuming via add_subdirectory/FetchContent.

Changes:

• Mark mat’s exported public include directory as a SYSTEM include in lib/CMakeLists.txt to suppress warnings originating from SDK public headers in consumer builds.
• Fix UNREFERENCED_PARAMETER(...) in ctmacros.hpp to reliably reference unused parameters on non-Windows compilers.
• Replace assert(!"message") with assert(false && "message") in ISemanticContext.hpp to avoid clang diagnostics.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
lib/include/public/ISemanticContext.hpp	Adjusts assertion idiom in enum-to-string switches to avoid clang warnings.
lib/include/public/ctmacros.hpp	Makes UNREFERENCED_PARAMETER actually reference parameters under gcc/clang to prevent -Wunused-parameter.
lib/CMakeLists.txt	Marks public include dir as SYSTEM for consumer builds (currently also impacts private includes in same call).

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

[baijumeswani]

Is it possible to align the build flags used in this repo's pipelines with those that ort expects so we don't see errors when integrating with ort in the future?