Initialize LLVM target and asmprinter for the native and extra targets. Uses some CMake hackery to get the native LLVM target name, since it only provides a conveniance function for initializing the native target and not the native asmprinter.

[Environment] 
DFLAGS=-I@RUNTIME_DIR@ -I@RUNTIME_DIR@/lib/common -L-L%@P%/../lib -d-version=Tango -defaultlib=@RUNTIME_AIO@ -debuglib=@RUNTIME_AIO@