possbily broken libopusfile, with dependencies libopus and openssl(!)

 libopusfile examples do *not* build, and I'm pretty sure we don't get any DLLs
 (just static libraries).

 For some reason, libopusfile depends on OpenSSL. OpenSSL, among various other
 faults, does not like to crossbuild. There is about three lines about
 crossbuilding in INSTALL.W32, but they're incorrect (i.e. following the
 instructions doesn't work). The same trick used for zlib and lua seems to work,
 but the lousy makefiles decide to execute some EXE as a shellscript, completely
 screwing up an interactive terminal. The build output is accordingly dumped
 into logfiles, and it is advised not to use the result for anything actually
 important.