Prevent extra calls to ToggleFeature for Feature64Bit and FeatureCMOV if they've already been enabled. The extra call ends up clearing the bit in FeatureBits since its a 'toggle'. Can't prove that anything was broken because of this since I don't think the FeatureBits for these are used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190920 91177308-0d34-0410-b5e6-96231b3b80d8
Make DynamicLibrary use ManagedStatic. This is pretty simple and should just work as 
advertised - but it does have the caveat that calls to DynamicLibrary::AddSymbol will 
"reset" if you shutdown llvm and try to come back for seconds.  This is a subtle 
behavior change, but I'm assuming that nobody is affected by it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190921 91177308-0d34-0410-b5e6-96231b3b80d8
Revert r190921.  It broke Windows.

I'll roll it back in when I have a chance to look at it in detail.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190923 91177308-0d34-0410-b5e6-96231b3b80d8