GMSL merge command

[Frazer Worley]

I want to translate the following

  VERA_LIBRARY_FILES+=a.vrl
  VERA_LIBRARY_FILES+=b.vrl
  VERA_LIBRARY_FILES+=c.vrl

into 

  vera_mload=a.vrl,b.vrl,c.vrl

I'd tried this:

    VERA_MLOAD= vera_mload=$(call merge,,,${VERA_LIBRARY_FILES}))

but it as issue with the 2nd comma - the separator in this case.

If I change the separator 

    VERA_MLOAD= vera_mload=$(call merge,+,${VERA_LIBRARY_FILES}))

>>  vera_mload=a.vrl+b.vrl+c.vrl

I get the correct type of functionality ... so I just need to know how to escape
the comma separator.

Thanks in advance,

-Frazer