Using GLAD as submodule does not generate .h and .c files when running CMake
I'm currently trying to build my project from sources and included GLAD as a submodule.
When I execute CMake with "configure" and "generate" the .h and .c do not appear.
In the GLAD CMakeLists.txt is the add_custom_command(...) which should generate those files.
When I run Python manually and execute your main.py, everything works, only CMake does not run and generate the header and source file?

It outputs only to following message, without having the two files generated
GLAD_SOURCES:
.../build/extern/glad/src/glad.c
.../build/extern/glad/include/glad/glad.h

I'm adding GLAD with
add_subdirectory(extern/glad)

Am I doing something wrong, or is something missing in my projects CMakeLists.txt?

Thanks for your help!
