wmc doesn't handle unix newlines correctly

Load an application that requires a missing Dll (for instance IrfanView 4.28 Setup which needs MFC42.DLL).
The error message will be truncated to something like "This application has failed to start because MC2D".

(Possibly, but probably not, related to CORE-5414)

win32csr.dll's CsrpFormatMessages function calls StringCbPrintfW with %hs in the format string in this case to create this message. The underlying _vsnwprintf function relies on mbtowc, which is implemented incorrectly using RtlMultiByteToUnicodeN (incompatible return values) in lib\sdk\crt\string\mbstowcs_nt.c and thus causes it to skip characters.

I'll be looking for a fix later; unless someone else has an idea first, of course