The ScGlobal::GetErrorString() shortcut produced error constants in the
localized UI language, which was wrong anyway when storing ODFF. Use compiler
with context instead to generate the proper symbols.

However, this currently maps all not defined Err:xxx to #NULL! so to preserve
those additional work is needed.

Change-Id: I1de7621d6349d5b00a5aac1cedc9f265c78c7db1