Define HAS_BOOL in source, not via compiler flags
Switch to Module::Build->depends_on

According to the Module::Build documentation, 'depends_on' is preferred
over 'dispatch' when calling actions from inside another action.
Remove dependency of Clownfish::CFC::Perl::Build on Charmonizer

Add a new field 'cflags' to the 'clownfish_params' Module::Build
property to pass additional compiler flags.
Set -fvisibility flag via charmonizer
Remove parcel privacy defines from cflags

They're baked into the generated XS code now.
Remove unneeded build action dependency