build(cmake): Add retail compatibility option in CMake config

[tintinhamans]

This pull request adds the RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME configuration
option in cmake/config-retail.cmake to make it easier to build retail or non-retail.

Will eventually be used for #2322

Tri-state, matching cmake/config-debug.cmake:

Value
DEFAULT	follows GameDefines.h
ON	forces RETAIL_COMPATIBLE_* guards on
OFF	forces RETAIL_COMPATIBLE_* guards off

The guard list is read from GameDefines.h at configure time, so new guards don't need CMake change.

The DEFAULT/ON/OFF dispatch is shared with config-debug.cmake via new helper macros in
config-macros.cmake (define_tristate_option).

Only the VC6 SP6 compiler produces a build that is CRC-compatible with retail,
other toolchains get a note. Skipped when OFF.

Retail compatibility: MSVC 19.44.35228.0 is not CRC-compatible with retail.
Retail builds need the VC6 SP6 compiler (12.00.8804).

[greptile-apps]

Greptile Summary

This PR adds a tri-state retail-compatibility build option and extracts shared CMake helpers for tri-state configuration.

• Collects retail compatibility guards from GameDefines.h during configuration.
• Supports DEFAULT, ON, and OFF retail compatibility settings.
• Reuses the shared tri-state helper for existing debug options.
• Warns when a requested retail-compatible build uses a compiler that cannot produce retail-compatible CRCs.

Confidence Score: 5/5

The PR appears safe to merge because no blocking failure remains within the eligible follow-up scope.

No blocking failure remains.

Important Files Changed

Filename	Overview
cmake/config-macros.cmake	Adds shared helpers for collecting compile-time guards and dispatching tri-state build options; no follow-up-eligible finding is retained.
cmake/config-retail.cmake	Adds the retail compatibility option, guard collection, and compiler compatibility notice; the previously questioned PRESERVE_* behavior was confirmed intentional.
cmake/config-debug.cmake	Migrates existing debug tri-state options to the shared helper.
cmake/config.cmake	Includes the new shared macro and retail configuration modules.

_{Reviews (16): Last reviewed commit: "refactor(cmake): Improve guarded option ..." | Re-trigger Greptile}

[bobtista]

Looks good to me, is there a reason we're not just adding ALL of the gamedefines macros? eg USE_BUFFERED_IO, USE_OBSOLETE_GENERALS_CODE, TELL_COMPUTER_IDENTITY_IN_LAN_LOBBY.

Also, maybe it's pedantic, but RTS_BUILD_OPTION_RETAIL_COMPATIBLE_PATHFINDING_ALLOCATION is probably a CMakeDependentOption of RTS_BUILD_OPTION_RETAIL_COMPATIBLE_PATHFINDING. Not needed though, this works as is.

[bobtista]

Should we revive this one? Are we using RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME? adding ALL of the gamedefines macros? If the individual switches remain, PATHFINDING_ALLOCATION should be dependent on PATHFINDING, and CI should compile at least one non-default configuration.

[tintinhamans]

Revived and simplified this based on the feedback.

The individual switches have been replaced with a single RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME option. Disabling it turns off all current RETAIL_COMPATIBLE_* defines.

I realized I didn't need to define every GameDefines.h macro as a CMake option because they can already be accessed with RTS_FLAGS.

[bobtista]

Should we have at least one of the RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME set to OFF for ci?

[tintinhamans]

Should we have at least one of the RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME set to OFF for ci?

Was planning on doing that in a follow-up PR.

[xezon]

Makes sense.

[xezon]

Has unaddressed comments. Needs rebase

[tintinhamans]

Has unaddressed comments. Needs rebase

Rebased onto main and updated the description for the option to better reflect that turning it off enables all the non-retail gameplay and simulation fixes.

[tintinhamans]

Updated to be tri-state and made it also detect RETAIL_COMPATIBLE_* guards dynamically.

Also warns when you use this feature with non-VC6SP6 compiler since that won't produce a truly retail-compatible build.

[xezon]

Looks clean now.

[xezon]

This version number is correct, yes? CL.EXE looks like this for me.

[tintinhamans]

Yes, CMake sees CMAKE_CXX_COMPILER_VERSION: 12.0.8804. You can confirm by looking at the configure output.