Don't compile in debugging info for Emscripten (non-native) - we just end up removing it anyway, and it massively slows down building (llvm-link in particular struggles with it).
Don't create a real KSharedDataCache for Emscripten.
Change the static library extension back to plain old '.a'.  See corresponding Qt commit 91a7045.
Allow the usage of llvm-link vs ar for native builds to be toggled via an environment variable: EMSCRIPTEN_USE_AR_FOR_STATIC_LIBRARIES equal to 'yes' will use ar.
Doh - looks like I was compiling the native version with Q_ASSERTs inactive :/ Remove a couple of asserts for EMSCRIPTEN - they don't seem to be important for us.
More SSL stuff, uncovered, all of a sudden(!), my the native emscripten build of Kate.
More stuff uncovered (all of a sudden) by Kate native emscripten build - don't build the StatusNotifierItem dbus stuff for Emscripten.
Stop CMake from complaining.
Thought I'd already done this ... anyway, don't use '.bc' as an extension for static libraries.