Error: conflicting Ddoc and obj generation options

[zhmt via Digitalmars-d-learn]

 mono-d is running on centos7 with options below:
first:
{
        "name": "ezsock",
        "targetType": "executable",
        "description": "A minimal D application.",
        "copyright": "Copyright © 2015, zhmt",
        "authors": ["zhmt"],
        "mainSourceFile": "source/app.d",
        "dependencies": {
                "gamelibd": {"path":"../gamelibd"}
        },
        "lflags":["-L../bin"],
        "workingDirectory":"../bin",
        "targetPath":"../bin",
}

second:

{
        "name": "gamelibd",
        "targetType": "sourceLibrary",
        "description": "A minimal D application.",
        "copyright": "Copyright © 2015, zhmt",
        "authors": ["zhmt"],
        "lflags":["-L../bin"],
        "workingDirectory":"../bin",
        "targetPath":"../bin",
}


The compilation complains that:

Compiling using dmd...
Error: conflicting Ddoc and obj generation options
FAIL 
.dub/build/application-debug-linux.posix-x86_64-dmd_2067-3E65324D543ED19695028F22620736D3/ 
ezsock executable
Error executing command build:
dmd failed with exit code 1.
Exit code 2


I cant figure out whats wrong with it. The almost same program 
compiles and runs
 well on mac osx.

I was stuck for almost a day, Thanks for your help in advance!