Autolinking was added to the frontend in 22912bc3b. It was disabled on
Linux in 198402dcf, and further constrained to be disabled on "linux-gnu"
in 83b4384fa. Since then, more flavors of Linux have become supported
by Swift: "linux-gnueabihf" in 4bf81e09d, and "freebsd" in f41b791d4.
Autolinking most likely does not work on any of these platforms, so
mark it as unsupported for now.
Other tests that only mark "linux-gnu" as unsupported do so for similar
reasons. Ensure unsupported tests for "linux-gnu" are also unsupported
on similar platforms.
Move helper function EmbedBitcode() from frontend_main.cpp to IRGen.cpp so we
can call it from performIRGeneration when the input file is Swift.
Add testing case to make sure that -embed-bitcode-marker option adds an
empty LLVM bitcode section.
rdar://19048891
Swift SVN r25577
