CMake uses a static library to pass files to the linker. CMake
does request windres to produce a COFF formatted object file, but
llvm-mingw's windres wrapper currently overrides it and produces
a .res (arch independent) formatted one instead. LLD doesn't support
such files in static libraries.

Just don't bother with the resource file for now, it's irrelevant
from VLC's point of view - it's only used for the executable and
shared library, neither of which are used by VLC.

Passing -DCMAKE_RC_COMPILER=FALSE on the cmake configuration line
sounds like a different workaround, but that doesn't seem to work
though - then we suddenly start getting -fPIC flags to the compiler,
which clang errors out on.

This can be dropped once llvm-mingw doesn't need to force the
windres output into the arch independent format.