Add a swift-client-api subdirectory containing a Swift source package
and a Makefile.in that compiles it into the "ServalClient" Swift module
using the Swift package manager. The Swift API contains the following
classes:
- ServalKeyring provides the operations: add, remove, set, list
- AbstractId and its specialisation SubscriberId, already in near-final
form, are data types for SID and the like
- ServalRestfulClient (internal) uses an HTTP client to access the
Serval DNA RESTful interface
Improve the REST /keyring/set operation to only alter the DID or Name if
the corresponding query parameter is supplied. Modify the internal
keyring_set_did() function to only assign the DID or Name if the
corresponding parameter is not a null pointer.
The configure script ensures that the Swift build target version is
10.10 or later when compiling for Mac OS-X, so that the package manager
will succeed.
Add autoconf macros for the Swift package manager.
