The daemon API is built as a Swift module called ServalDNA.
The new CliContext class allows easy implementation of CLI output using
Swift code. The new CliContextFile subclass is the obvious first
implementation, equivalent to cli_stdio.c. The 'servaldswift'
executable now uses CliContextFile to print its CLI output to standard
output.
The new delegated log output support constructs each log line in a
buffer and prints it by calling the delegate's 'print' function at
end-of-line. The 'servaldswift' executable now provides a log output
delegate in Swift that simply prints to standard error, replacing
log_output_console.o, which is omitted from its link.
If the Swift 3 or Swift 4 compiler is present or passed to the configure
script in the SWIFTC variable, then the Makefile will compile a Swift
'servaldswift' executable to ensure that the module map links correctly
into a stand-alone Swift program.
Use the gold linker if supported, to avoid relocation errors on symbols
produced by Swift when linking dynamic libraries.
