rpcrt4: Dynamically allocate the buffer if the fixed size one isn't large enough. Don't return an inappropriate error if we fail to get the status text, it's only used for diagnostics.

CodeWeavers did this work for supporting the optional HTTP connection
method of Outlook 2003/2007 (must be running with Windows versions set
to XP or higher to see this option).

This was written before Microsoft publicly released a specification
for the RPC over HTTP protocol and so was developed by examining
traffic flowing between a Windows client and an IIS server.

CodeWeavers did this work for supporting Outlook 2007.

Another fix for the office 2007 sp1 installer.

These tests confirm that a feature is reported as advertised if only
one of its components is missing.

Fixes an issue with .Net 3.0 where it does not install a new
fusion.dll but does add a key to the registery. The fact that a new
dll is not installed has been verified on windows.

So, compute the offset by subtracting the function address.