Fixing versions

- Added --version-suffix to build and publish
- Support reading DOTNET_* version variables everywhere versions can be read
- Show the commit sha in dotnet --version
- Added tests that check the assembly output version
- Set DOTNET_BUILD_VERSION when producing the CLI app itself so that it has the version information stamped in for help.

scripts/dotnet-cli-build/CompileTargets.cs

@@ -157,11 +157,14 @@ namespace Microsoft.DotNet.Cli.Build
 
             var configuration = c.BuildContext.Get<string>("Configuration");
             var binDir = Path.Combine(outputDir, "bin");
+            var buildVesion = c.BuildContext.Get<BuildVersion>("BuildVersion");
 
             Mkdirp(binDir);
 
             foreach (var project in ProjectsToPublish)
             {
+                // TODO: Use the flag once we get a full build round tripped
+                // --version-suffix buildVesion.VersionSuffix
                 dotnet.Publish(
                     "--native-subdirectory",
                     "--output",
@@ -169,6 +172,7 @@ namespace Microsoft.DotNet.Cli.Build
                     "--configuration",
                     configuration,
                     Path.Combine(c.BuildContext.BuildDirectory, "src", project))
+                    .Environment("DOTNET_BUILD_VERSION", buildVesion.VersionSuffix)
                     .Execute()
                     .EnsureSuccessful();
             }
@@ -210,7 +214,7 @@ namespace Microsoft.DotNet.Cli.Build
             }
 
             // Generate .version file
-            var version = c.BuildContext.Get<BuildVersion>("BuildVersion").SimpleVersion;
+            var version = buildVesion.SimpleVersion;
             var content = $@"{c.BuildContext["CommitHash"]}{Environment.NewLine}{version}{Environment.NewLine}";
             File.WriteAllText(Path.Combine(outputDir, ".version"), content);