Which .eclass-es to inherit?

xbuild: compile sources with xbuild utility
msbuild: compile sources with msbuild utility
mono-pkg-config: installs library into filesystem and register it in .pc-file for other applications
gac: contain functions to register .dll in GAC
machine: allows to add elements into machine.config file(s?)
dotnet: this is base eclass for msbuild.eclass and xbuild.eclass
nupkg: contain functions to create .nupkg file from .nuspec file
mono-env: it support compilation of native libraries which should know .net platform specific (where to see examples of such specific?)
multilib: strange library for 32 and 64-bit builds of native libraries
nuget: should allow to install .nuget packages from nuget.org site in binary form
versionator
eutils
autotools
autotools-utils
flag-o-matic
java-pkg-2
vcs-snapshot
git-r3
git-2
rpm