Load oleaut32.dll for widestrings on demand.

Same as !449 (merged) but more dubious because it targets a narrow range of applications.

widestring on Windows is an UTF-16 string type managed with oleaut32.dll calls and required solely to exchange BSTRs with COM APIs; using it in other scenarios instead of unicodestring is a legacy artefact. (Whether widestrings in variants are “COM interaction” or “legacy artefacts” is up to the reader.)

All but the simplest applications load oleaut32.dll anyway (often indirectly), however I think that respecting simplest applications is a good thing. (The other time, the FPC itself could be among these applications if not one ole32.dll:CoTaskMemFree...) More substantial proof of viability: Windows libraries themselves do the equivalent of what I propose, for example, my winmm.dll delay-loads oleaut32.dll (according to the Dependency Walker) roughly for the same functions (SysAllocString, SysFreeString), to never load in simple scenarios.