Migrate from Conan 1 to Conan 2

[joamag]

Summary

• Migrated build system from Conan 1 to Conan 2
• Updated conanfile.txt generators: make/cmake → CMakeToolchain/CMakeDeps/MakeDeps
• Modernized CMakeLists.txt: replaced conan_basic_setup() with find_package() and CMake targets (PNG::PNG, ZLIB::ZLIB)
• Updated Makefile to include conandeps.mak (Conan 2) instead of conanbuildinfo.mak (Conan 1)
• Updated all CI workflows to use Conan 2 CLI (conan profile detect, conan install --build=missing, CMAKE_TOOLCHAIN_FILE)

Test plan

• Verify Linux GCC CMake builds pass
• Verify Windows CMake build passes
• Verify macOS CMake build passes
• Verify plain Make builds (GCC/Clang) still work (no Conan changes)
• Verify Python extension builds are unaffected

🤖 Generated with Claude Code

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat/conan-2

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[Copilot]

Pull request overview

Migrates the project’s dependency/build integration from Conan 1 to Conan 2 by switching to Conan 2 generators and updating the CMake/Make/CI wiring accordingly.

Changes:

• Updated conanfile.txt generators to Conan 2 (CMakeToolchain, CMakeDeps, MakeDeps).
• Modernized CMakeLists.txt to use find_package() + imported targets instead of conan_basic_setup().
• Updated CI workflows to use Conan 2 CLI (conan profile detect, conan install --build=missing, toolchain file).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
conanfile.txt	Switches to Conan 2 generators for CMake and Make integration.
Makefile	Attempts to consume Conan 2 make deps via conandeps.mak.
CMakeLists.txt	Replaces Conan 1 CMake integration with find_package() and target-based linking.
CHANGELOG.md	Notes Conan 2 migration in changelog.
.github/workflows/main.yml	Updates CI to install/use Conan 2 and pass the generated CMake toolchain.

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[Copilot]

find_package(PNG)/find_package(ZLIB) without CONFIG will prefer CMake’s built-in Find modules when available, which can cause the build to link against system libraries instead of the Conan-resolved ones. To ensure Conan’s CMakeDeps packages are used consistently, use find_package(PNG CONFIG REQUIRED) and find_package(ZLIB CONFIG REQUIRED) (or set CMAKE_FIND_PACKAGE_PREFER_CONFIG=ON).

Suggested change

	find_package(PNG REQUIRED)
	find_package(ZLIB REQUIRED)
	find_package(PNG CONFIG REQUIRED)
	find_package(ZLIB CONFIG REQUIRED)

[Copilot]

This job installs libpng-dev while also using Conan + CMakeDeps. Combined with find_package(PNG) (module mode), this can cause CMake to resolve PNG from the system rather than Conan, undermining the Conan 2 migration and risking mismatched dependency versions. Consider removing libpng-dev here (and relying on Conan), or force config-mode find_package(... CONFIG ...) so Conan’s packages win.

[Copilot]

The Makefile now includes conandeps.mak, but the rest of the Makefile still consumes legacy Conan 1 CONAN_* variables (CONAN_CFLAGS, CONAN_INCLUDE_DIRS, CONAN_LIBS, etc.). Conan 2’s MakeDeps generator emits a different set of variables, so simply swapping the included filename is unlikely to make Conan-based make builds pick up the right flags/paths. Update the Makefile to use the variables produced by MakeDeps (or switch generators to match the existing CONAN_* usage).