[dune-pdelab] dune-typetree installs cxx11_initializer_list.m4 which is already installed by dune-common

[Ansgar Burchardt]

Hi,

dune-typetree installs cxx11_initializer_list.m4, but the file is
already installed by dune-common. Only one module should ship it,
probably dune-common if it is used elsewhere.

FindPackageMultipass.cmake and ResolveCompilerPaths.cmake in
cmake/modules may have the same problem. These are also included in
dune-pdelab and don't seem to be used in dune-typetree at all.

Ansgar