If HTTP charset header is empty, do not append content encoding to Content-Type header
Add unit test for Content-Type header with and without charset set
xbuild: include a Microsoft.Portable.Common.targets file (for F#)

F# PCL projects expect this file to exist in:
$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.Common.targets

So in order to avoid pristine F# PCL projects (created from VS) fail
the build that file has to exist, and import the Core targets like
its CSharp counterpart (Microsoft.Portable.CSharp.targets) does.

Fixes https://bugzilla.xamarin.com/show_bug.cgi?id=17906
Correctly set Count after call to ConcurrentStack.PushRange()
Merge pull request #931 from exony-craigminihan/bugzilla#18097

Correctly set Count after call to ConcurrentStack.PushRange()
[mdoc] Fix the tests.
[corlib] Implement CultureInfo.ClearCachedData. Fixes #18162
Fix the build.
[sdb] Add some debug output to help track down #18100.
[runtime] Implement wapi_process_get_path () on non osx platforms by falling back to get_process_name_from_proc ().
[runtime] Fix a memory leak.
[runtime] Fix a memory leak.
[runtime] Fix a memory leak.
[corlib] Parse datetime string using culture calendar. Fixes #18052
[runtime] Move some counters to the mono-counters infrastructure, to break dependencies between utils/ and metadata/.
Really fix the build.
[jit] Implement the push/pop LMF code in IR on windows too.
[runtime] Disable MONO_XEN_OPT on windows.
[runtime] Fix loaded llvm support.
Disable the test-messages test on win32, its not needed.