Apparently the MinGW header files don't declare it, despite it being
part of liblphlapi.a. More confusingly, it didn't break anything for
64-bit builds because the compiler used an implicit declaration that
matched the link-time symbol name. Alas, no such luck for 32-bit
builds, since the implicit declaration was not annotated with the @48
stdcall argument stack size, so the build died at link time.
