rust: update to 1.22.1.
rust: update to 1.22.1.

Use llvm3.9 so we can move llvm to 5.

coredumb/void-packages,floGik/void-packages,floGik/void-packages,NeoChontrix/void-packages,necrophcodr/void-packages,floGik/void-packages,coredumb/void-packages,NeoChontrix/void-packages,EaterOfCode/void-packages,necrophcodr/void-packages,coredumb/void-packages,EaterOfCode/void-packages,floGik/void-packages,NeoChontrix/void-packages,floGik/void-packages,NeoChontrix/void-packages,NeoChontrix/void-packages,coredumb/void-packages,floGik/void-packages,NeoChontrix/void-packages,EaterOfCode/void-packages,necrophcodr/void-packages,necrophcodr/void-packages,coredumb/void-packages,coredumb/void-packages,EaterOfCode/void-packages,EaterOfCode/void-packages,necrophcodr/void-packages