CPack: Add NuGet support

Create a CPack generator that uses `nuget.exe` to create packages:

    https://docs.microsoft.com/en-us/nuget/what-is-nuget

NuGet packages could be easily produced from a `*.nuspec` file (running
`nuget pack` in the directory w/ the spec file).  The spec filename does
not affect the result `*.nupkg` name -- only `id` and `version` elements
of the spec are used (by NuGet).

Some implementation details:

* Minimize C++ code -- use CMake script do to the job. It just let the
  base class (`cmCPackGenerator`) to preinstall everything to a temp
  directory, render the spec file and run `nuget pack` in it, harvesting
  `*.nupkg` files...;

* Ignore package name (and use default paths) prepared by the base class
  (only `CPACK_TEMPORARY_DIRECTORY` is important) -- final package
  filename is a responsibility of NuGet, so after generation just scan the
  temp directory for the result `*.nupkg` file(s) and update
  `packageFileNames` data-member of the generator;

* The generator supports _all-in-one_ (default), _one-group-per-package_
  and _one-component-per-package_ modes.

1 files changed, 12 insertions, 0 deletions

diff --git a/Tests/CPackComponentsForAll/CMakeLists.txt b/Tests/CPackComponentsForAll/CMakeLists.txt
index 3440843..f2e4fcd 100644
--- a/Tests/CPackComponentsForAll/CMakeLists.txt
+++ b/Tests/CPackComponentsForAll/CMakeLists.txt
@@ -168,6 +168,18 @@ set(CPACK_RPM_RELOCATION_PATHS "${CMAKE_INSTALL_INCLUDEDIR}"
 # set CPACK_DEBIAN_FILE_NAME to use default package name format
 set(CPACK_DEBIAN_FILE_NAME "DEB-DEFAULT")
 
+# set some tags for NuGet packages
+# 1. all in one pacakge
+set(CPACK_NUGET_PACKAGE_TAGS "nuget" "unit" "test" "all-in-one")
+# 2. per component packages
+set(CPACK_NUGET_APPLICATIONS_PACKAGE_TAGS "nuget" "unit" "test" "applications")
+set(CPACK_NUGET_LIBRARIES_PACKAGE_TAGS "nuget" "unit" "test" "libraries")
+set(CPACK_NUGET_HEADERS_PACKAGE_TAGS "nuget" "unit" "test" "headers")
+set(CPACK_NUGET_UNSPECIFIED_PACKAGE_TAGS "nuget" "unit" "test" "uNsP3c1FiEd")
+# 3. per group packages
+set(CPACK_NUGET_RUNTIME_PACKAGE_TAGS "nuget" "unit" "test" "run-time")
+set(CPACK_NUGET_DEVELOPMENT_PACKAGE_TAGS "nuget" "unit" "test" "development")
+
 # We may use the CPack specific config file in order
 # to tailor CPack behavior on a CPack generator specific way
 # (Behavior would be different for RPM or TGZ or DEB ...)