To summarise, there are 2 projectdefinition.txt files.
on main / sdk level, Define which project (plugins, etc.)
Example:
Platform=Win64;OSX
Type=Solution
// defines the level of rigour of the source processor's style check
stylecheck.level=0
Solution=\
plugins/cinema4dsdk;\
plugins/maxonsdk.module;\
plugins/commandline;\
plugins/CommandLineRendering
on plugin level, // Configuration of a custom solution in the projectdefinition.txt file
Example:
// Supported platforms
Platform=Win64;OSX
// Type of project
Type=DLL
// this plugin depends on these frameworks:
APIS=\
cinema.framework; \
misc.framework; \
image.framework; \
core.framework; \
python.framework
// Enable some advanced classic API support; not needed for hybrid plugins
C4D=true
// Plug-in code-style check level
stylecheck.level=0
// Custom ID
ModuleId=net.maxonexample.commandlinerender