Add language-specific x-targeting targets to new packages (#1114)
Add language-specific x-targeting targets to new packages (#1114)

Manual port of #1110 to the new `.nuspec`s
cdmihai/msbuild,cdmihai/msbuild,sean-gilliam/msbuild,mono/msbuild,rainersigwald/msbuild,mono/msbuild,jeffkl/msbuild,rainersigwald/msbuild,rainersigwald/msbuild,jeffkl/msbuild,Microsoft/msbuild,Microsoft/msbuild,AndyGerlicher/msbuild,sean-gilliam/msbuild,chipitsine/msbuild,cdmihai/msbuild,chipitsine/msbuild,chipitsine/msbuild,mono/msbuild,sean-gilliam/msbuild,jeffkl/msbuild,rainersigwald/msbuild,cdmihai/msbuild,chipitsine/msbuild,sean-gilliam/msbuild,Microsoft/msbuild,jeffkl/msbuild,AndyGerlicher/msbuild,Microsoft/msbuild,mono/msbuild,AndyGerlicher/msbuild,AndyGerlicher/msbuild