compiling DLLs with ipyc.exe asks erroneously for /main

[CFTSeb]

Description

I try to compile a DLL, containing several python-Files with /target:dll. Although in https://github.com/IronLanguages/ironpython2/blob/master/Src/IronPythonCompiler/README.md option /main is only valid for /target:exe, it aks me for a main in the dll context. The result (if I provide an arbitrarily "/main" file) does also not behave like expected. I switched to clr.CompileModules (which worked correctly). But I need ipyc.exe because of the meta-info features (fileversion productname ...)

Steps to Reproduce

ipyc.exe /out:test.dll /target:dll Tom.py Jerry.py

Expected behavior: output of test.dll

Actual behavior: ERROR: No files or main defined

Versions 2.7.7, 2.7.8, 2.7.11,

at least 2.7.7, 2.7.8, 2.7.11,