Add LTCG flags to compile_windows.bat for BinSkim BA6006 compliance

[Copilot]

Summary

Windows DLL/EXE builds were failing BinSkim BA6006 checks and emitting MSVC linker warnings about /LTCG specified but no code generation required. Root cause: objects weren't compiled with /GL (whole-program optimization) before linking with /LTCG.

Changes

Added LTCG flags to all 6 build commands in compile_windows.bat:

• Compiler: Added /GL flag to enable whole-program optimization
• Linker: Added /LTCG flag to enable link-time code generation

Affected binaries:

• attach_x86.dll / attach_amd64.dll
• run_code_on_dllmain_x86.dll / run_code_on_dllmain_amd64.dll
• inject_dll_x86.exe / inject_dll_amd64.exe

Before:

cl /EHsc /Zi /O1 /W3 /LD /MD /Qspectre attach.cpp /link /PROFILE /GUARD:CF /CETCOMPAT /out:attach_x86.dll

After:

cl /EHsc /Zi /O1 /W3 /LD /MD /GL /Qspectre attach.cpp /link /LTCG /PROFILE /GUARD:CF /CETCOMPAT /out:attach_x86.dll

This ensures each object passed to a /LTCG link step was compiled with /GL, satisfying both MSVC requirements and BinSkim security checks.

Original prompt

Update 'compile_windows.bat' so that all DLL and EXE build steps requiring Link-Time Code Generation (LTCG) pass BinSkim checks and do not emit the MSVC linker warning about '/LTCG specified but no code generation required'.

Specifically:

• Add '/GL' to each 'cl' command that produces a DLL or EXE that is checked by BinSkim (such as attach_x86.dll, attach_amd64.dll, inject_dll_amd64.exe, run_code_on_dllmain_x86.dll, run_code_on_dllmain_amd64.dll).
• Add '/LTCG' to the '/link' step for those same build products if not present.
• Ensure that every object passed to a link step with '/LTCG' is built with '/GL'.
• The result must both pass BinSkim BA6006 and suppress the 'LINK : /LTCG specified but no code generation required' warning from MSVC.
• Do not modify other unrelated aspects of the script.

Tested by: Ensuring the changed commands match MSVC documentation for LTCG and previous user feedback, though script runtime or build output validation is out-of-scope for this change.

This pull request was created from Copilot chat.

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