A bit more cleanup with respect to using LLDB_CONFIG_XXX defines outside of

the lldb/source/Host/*.cpp and lldb/source/Host/*/*.cpp directories. The only
offenders are the command completion and the StreamFile.cpp. 

I will soon modify StreamFile.cpp to use a lldb/source/Host/File.cpp so that
all file open, close, read, write, seek, are abstracted into the host layer
as well, then this will be gone.

llvm-svn: 125082