build(cmake): Add retail compatibility options and features in CMake config

[tintinhamans]

This pull request adds several new build configuration options to cmake/config-build.cmake to allow finer control over compatibility and feature toggles.

Will eventually be used for #2322

[greptile-apps]

Greptile Summary

Added 12 new CMake build options to enable fine-grained control over retail compatibility and feature toggles:

Retail Compatibility Options (default ON):

• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_CRC - CRC compatibility with retail Generals 1.08/Zero Hour 1.04
• RTS_BUILD_OPTION_PRESERVE_RETAIL_BEHAVIOR - Retain retail behavior
• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_XFER_SAVE - Xfer Save compatibility
• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_PATHFINDING - Retail pathfinding with fixed fallback
• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_PATHFINDING_ALLOCATION - Retail pathfinding memory allocation
• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_NETWORKING - Retail networking behavior
• RTS_BUILD_OPTION_RETAIL_COMPATIBLE_AIGROUP - AIGroup logic CRC compatibility

Feature Options (default ON):

• RTS_BUILD_OPTION_ENABLE_GAMETEXT_SUBSTITUTES - Provide fallback text for missing translations
• RTS_BUILD_OPTION_ENABLE_CONFIGURABLE_SHROUD - Configurable shroud in GlobalData
• RTS_BUILD_OPTION_ENABLE_FILESYSTEM_EXISTENCE_CACHE - Cache for file existence checks
• RTS_BUILD_OPTION_PRIORITIZE_TEXTURES_BY_SIZE - Texture prioritization by size
• RTS_BUILD_OPTION_ENABLE_GUI_HACKS - Window settings overrides

Implementation follows the existing pattern: when options are ON (default), CMake doesn't define the macros, allowing GameDefines.h to provide default values of 1. When options are OFF, CMake defines them as 0.

Confidence Score: 5/5

• This PR is safe to merge - it only adds new build configuration options without modifying existing code.
• The implementation is clean, consistent, and follows established patterns exactly. All 12 options follow the same structure with proper option(), add_feature_info(), and conditional target_compile_definitions() blocks. The code is purely additive with no changes to existing logic. Verified that all macros have corresponding defaults in GameDefines.h.
• No files require special attention

Important Files Changed

Filename	Overview
cmake/config-build.cmake	Added 12 new build options for retail compatibility and feature toggles with corresponding feature info and compile definitions. Clean implementation follows existing patterns.

_{Last reviewed commit: b3fca3b}

[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.

[xezon]

That is a lot of control.

To simplify, we can combine the 6 *_RETAIL_COMPATIBLE_* options to 1 RTS_BUILD_OPTION_RETAIL_COMPATIBLE_GAME

[Mauller]

Yes this would be better if we want a pure non retail compatible build, individual control is only really helpful during development, but most of us alter the defines directly during testing.