extra_ghc_opts syntax

[S.D.Mechveliani]

Dear  ghc-5.02-linux-i386-unknown,

You understand        extra_ghc_opts = ["-v","-O"]
when using a package,
but not               extra_ghc_opts = ["-v -O"]

And I intended to set in Makefile
  ...
  ex = -ddump-hi-diffs -fglasgow-exts -fallow-overlapping-instances 
       -fallow-undecidable-instances -fno-warn-overlapping-patterns 
       -fwarn-unused-binds -fwarn-unused-matches -fwarn-unused-imports
       ...

  pk = Package {...
                extra_ghc_opts = ["\"$(ex)\""],
                ...
               }

  ... echo $(pk) | ghc-pkg -a 


What may be a reasonable way out?

-----------------
Serge Mechveliani
mechvel@botik.ru