Export `luisa-config.h` and pkg-config file for non-CMake build systems

[Copilot]

Overview

This PR adds support for using LuisaCompute with build systems other than CMake by generating and installing a configuration header (luisa-config.h) and a pkg-config file (luisacompute.pc) during CMake installation.

Motivation

Users who want to integrate LuisaCompute into projects using build systems like Make, Bazel, Meson, or others need access to the compile-time configuration that CMake normally handles automatically. This PR addresses that need by exporting configuration information in standard formats.

Changes

New Files

1. include/luisa/luisa-config.h.in - Template for the configuration header containing:

   • Version information via inclusion of existing version.h header
   • Core feature flags (LUISA_ENABLE_IR, LUISA_ENABLE_DSL, LUISA_ENABLE_GUI, LUISA_ENABLE_API, LUISA_ENABLE_XIR, LUISA_ENABLE_CLANGCXX, LUISA_ENABLE_TENSOR)
   • Platform detection macros (LUISA_PLATFORM_WINDOWS, LUISA_PLATFORM_UNIX, LUISA_PLATFORM_APPLE)
   • Platform-specific features (LUISA_ENABLE_WAYLAND)
   • System library usage flags (LUISA_USE_SYSTEM_STL, LUISA_USE_SYSTEM_SPDLOG, LUISA_USE_SYSTEM_XXHASH, LUISA_USE_SYSTEM_MAGIC_ENUM, LUISA_USE_SYSTEM_GLFW, LUISA_USE_SYSTEM_REPROC, LUISA_USE_SYSTEM_YYJSON, LUISA_USE_SYSTEM_MARL, LUISA_USE_SYSTEM_LMDB, LUISA_USE_SYSTEM_VULKAN)
   • Compiler feature requirements (LUISA_COMPUTE_C_STANDARD, LUISA_COMPUTE_CXX_STANDARD)

2. luisacompute.pc.in - pkg-config template providing:

   • Package metadata (name, description, version, URL)
   • Compiler flags with all relevant compile definitions
   • Library paths for linking

Modified Files

1. CMakeLists.txt:

   • Systematically collects all compile definitions from CMake configuration options
   • Uses helper function for elegant pkg-config flag population
   • Generates luisa-config.h and luisacompute.pc during configuration
   • Installs both files to appropriate locations (<prefix>/include/luisa/ and <prefix>/lib/pkgconfig/)
   • Adds generated include directory to build interface

2. BUILD.md:

   • Added "Using LuisaCompute with Other Build Systems" section
   • Documents the configuration header and its macros
   • Provides pkg-config usage examples
   • Includes Makefile integration example

Usage

After installing LuisaCompute with CMake:

cmake --install <build-dir> --prefix /path/to/install

Users can now:

Include the configuration header:

#include <luisa/luisa-config.h>

#if LUISA_ENABLE_DSL
    // Use DSL features
#endif

Use pkg-config for build configuration:

# Get compiler flags
pkg-config --cflags luisacompute

# Get linker flags  
pkg-config --libs luisacompute

# Use in a Makefile
CXXFLAGS += $(shell pkg-config --cflags luisacompute)
LDFLAGS += $(shell pkg-config --libs luisacompute)

Testing

Verified that:

• Configuration files are correctly generated with different CMake options (DSL enabled/disabled, system libraries, different platforms)
• All compile definitions are properly collected and exported
• Generated files are properly installed during cmake --install
• pkg-config integration works correctly with all flags
• C++ programs can successfully compile using the exported configuration
• Version information is correctly pulled from existing version.h header

Fixes #117

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Export luisa-config.h for other build systems than CMake</issue_title> <issue_description>So we can better support the use cases like in LuisaGroup/LuisaCompute#117.</issue_description>

<agent_instructions>collect compile definitions and options in CMakeLists and generate luisa-config.h on CMake install, and optionally a pkg-config file with proper compile and link flags</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes LuisaGroup/LuisaCompute#118

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Mike-Leo-Smith]

@copilot Please fix this.

[Copilot]

The flags look not fully collected. Please review all CMakeLists including those in the subdirectory. Also, you might notice that there is already a version header under the include dir so dont repeat...

Fixed in commit 8c59a33. Changes:

• luisa-config.h now includes version.h instead of duplicating version macros
• Added all LUISA_ENABLE_* flags (IR, DSL, GUI, API, XIR, CLANGCXX, TENSOR)
• Added all LUISA_USE_SYSTEM_* flags (STL, SPDLOG, XXHASH, MAGIC_ENUM, GLFW, REPROC, YYJSON, MARL, LMDB, VULKAN)
• Added all platform flags (WINDOWS, UNIX, APPLE, WAYLAND)
• Used a helper function to cleanly populate pkg-config flags

@copilot Please fix this.

Fixed in d46f695.