How to build dub from source on Raspberry PI 4 , freebsd-OS, having a functional ldc2 compiler

[Alain De Vos]

Cloned the git sources of dub.
Done:
export CC=gcc
ldc2 ./build.d
Then running build spits out:

Using pre-existing version file. To force a rebuild, provide an 
explicit version (first argument) or remove: 
/home/freebsd/Git_app/dub/./source/dub/version_.d
Building dub using /usr/local/bin/ldc2 (dflags: ["-g", "-O", 
"-w"]), this may take a while...
Command `["/usr/local/bin/ldc2", 
"-of/home/freebsd/Git_app/dub/./bin/dub", 
"-I/home/freebsd/Git_app/dub/./source", "-version=DubUseCurl", 
"-version=DubApplication", "-g", "-O", "-w", "@build-files.txt"]` 
failed, output was:
ldc2: for the --version option: does not allow a value! 
'DubUseCurl' specified.
ldc2: for the --version option: does not allow a value! 
'DubApplication' specified.

What is this ?

It gives me the option LDC but it is ldc2 ?