Fix dependencies.
Fix return types.
Don't depend on png.h to pull in string.h.
Make sure the upper limit is applied.
Fix return types.
gtar doesn't seem to be needed any longer.
Use plain tar.
Explicitly request C++11 when building with clang.
Define classes before using them.
Inline definitions inside functions are invalid. Remove constructor that
calls non-existing parent constructor.
Prefer bsdtar
Must link against libexecinfo on newer NetBSD.
Don't use extern inline with Clang as the redefinitions conflict with C99.
Define default_context_to before using it in templates.
Needs _KMEMUSER on NetBSD/current.
Uses <typeinfo>
Drop z flag, explicitly pull in tar.
Don't add default arguments when implementing a function.
Fix return types.