Update build/resources/backend_versions.json during cmake

[superm1]

Move resource copying from CMake configuration phase to build phase with proper file dependency tracking using CONFIGURE_DEPENDS and DEPENDS. This ensures that changes to src/cpp/resources files are detected and copied to the build directory on each build.

Fixes #1104

[superm1]

This seems not to work as I intended on some versions of cmake. Marking as a draft for now.

[superm1]

This seems not to work as I intended on some versions of cmake. Marking as a draft for now.

I've fixed the issue, it was an incorrect use of the DEPENDS keyword.

[Copilot]

Pull request overview

Moves copying of C++ runtime resource files out of the CMake configure step and into the build step, so resource changes (e.g., backend_versions.json) are picked up by cmake --build without requiring reconfiguration (Fixes #1104).

Changes:

• Adds a copy_resources build target driven by a globbed resource file list (CONFIGURE_DEPENDS) to trigger rebuild-time copying.
• Copies src/cpp/resources/ into ${CMAKE_BINARY_DIR}/resources via a custom command with dependency tracking.
• Ensures the main executable depends on the resource-copying target.

---

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[Copilot]

The stamp file output is placed inside the resources directory (${CMAKE_BINARY_DIR}/resources/.resource_timestamp). Since the build later copies/installs the entire resources directory, this dotfile will end up in the runtime output and in packaged installs. Consider moving the stamp outside the resources tree (e.g., ${CMAKE_CURRENT_BINARY_DIR}/resources.stamp) or explicitly excluding it from the subsequent copy/install steps.

Suggested change

	OUTPUT ${CMAKE_BINARY_DIR}/resources/.resource_timestamp
	COMMAND ${CMAKE_COMMAND} -E copy_directory
	${CMAKE_CURRENT_SOURCE_DIR}/src/cpp/resources
	${CMAKE_BINARY_DIR}/resources
	COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/resources/.resource_timestamp
	DEPENDS ${RESOURCE_FILES}
	COMMENT "Copying resources to build directory"
	)
	add_custom_target(copy_resources ALL
	DEPENDS ${CMAKE_BINARY_DIR}/resources/.resource_timestamp
	OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/resources.stamp
	COMMAND ${CMAKE_COMMAND} -E copy_directory
	${CMAKE_CURRENT_SOURCE_DIR}/src/cpp/resources
	${CMAKE_BINARY_DIR}/resources
	COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_CURRENT_BINARY_DIR}/resources.stamp
	DEPENDS ${RESOURCE_FILES}
	COMMENT "Copying resources to build directory"
	)
	add_custom_target(copy_resources ALL
	DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/resources.stamp

[Copilot]

The custom command writes ${CMAKE_BINARY_DIR}/resources/.resource_timestamp, but the resources directory may not exist on a clean build. Since the next step touches a file inside that directory, add an explicit directory creation step (e.g., ${CMAKE_COMMAND} -E make_directory ${CMAKE_BINARY_DIR}/resources) before copy/touch to avoid build failures on fresh build trees.

[Copilot]

file(GLOB_RECURSE ...) will include directories by default. Adding LIST_DIRECTORIES false would keep RESOURCE_FILES limited to actual files, avoiding spurious dependencies/rebuild triggers from directory timestamp changes.

Suggested change

	file(GLOB_RECURSE RESOURCE_FILES
	file(GLOB_RECURSE RESOURCE_FILES
	LIST_DIRECTORIES false