cwrappers and "" empty quoted arguments

[coypu%sdf.org@localhost]

hi folks,

I have an issue with the updated version of mono, wip/mono6.
it builds fine outside of pkgsrc, but cwrappers seems to break its use
of the command line.

It's running commands like:

MONO_PATH="./../../class/lib/build:$MONO_PATH" /home/fly/pkgsrc/wip/mono6/work/mono-6.0.0.313/runtime/mono-wrapper  ./../../class/lib/build/gen
sources.exe --basedir:./Test --strict --platformsdir:./../../build "../../build/deps/_xbuild_12_Microsoft.Build.Framework_test.dll.sources" "Mi
crosoft.Build.Framework_test.dll" "" "xbuild_12"

And I suspect cwrappers doesn't like the use of "" and drops it (?) so
the build misbehaves.
Quoting it as \"\" helps.

Anything I could do to improve on the situation?