fatal error U1033: syntax error : '-Dperspective_to_perspective_EXPORTS' unexpected

[SamuelMarks]

-DAFTEREFFECTS_SDK="<path to March 2021 version>/AfterEffectsSDK"
-DAFTEREFFECTS_LOCATION="C:/Program Files/Adobe/Adobe After Effects 2021"

Scanning dependencies of target perspective_to_perspective_resources
Microsoft (R) C/C++ Optimizing Compiler Version 19.28.29915 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

PiPL.r
Microsoft (R) C/C++ Optimizing Compiler Version 19.28.29915 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

PiPL.rrc
CMakeFiles\perspective_to_perspective.dir\flags.make(6) : fatal error U1033: syntax error : '-Dperspective_to_perspective_EXPORTS' unexpected
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\bin\HostX64\x64\nmake.exe"' : return code '0x2'
Stop.
NMAKE : fatal error U1077: '"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\bin\HostX64\x64\nmake.exe"' : return code '0x2'
Stop.
[  0%] Built target perspective_to_perspective_resources

Which I believe is this line:

COMMAND cl.exe /I "${AFTEREFFECTS_SDK}/Examples/Headers" /EP "${CMAKE_SOURCE_DIR}/perspective_to_equirectangular/PiPL.r" > "${CMAKE_SOURCE_DIR}/perspective_to_equirectangular/PiPL.rr"

https://github.com/Gorialis/aftereffects_spatial_media_plugins/blob/2495315/CMakeLists.txt#L69

EDIT: In the meantime I cheated with https://github.com/pavelliavonau/cmakeconverter to create a CMakeLists.txt from the MSVC solution. Then I edited it to remove all the hardcoded paths and duplicate branches. Surprisingly it works.