The old NMExportedConnection was used for both client and server-side classes,
which was a mistake and made the code very complicated to follow. Additionally,
all PolicyKit operations were synchronous, and PK operations can block for a
long time (ie for user input) before returning, so they need to be async. But
NMExportedConnection and NMSysconfigConnection didn't allow for async PK ops
at all.
Use this opportunity to clean up the mess and create GInterfaces that both
server and client objects implement, so that the connection editor and applet
can operate on generic objects like they did before (using the interfaces) but
can perform specific operations (like async PK verification of callers) depending
on whether they are local or remote or whatever.
The only thing that doesn't work yet is the system-settings service's
"auto eth" connections for ethernet devices that don't have an existing
connection. Might also have issues with unmanaged devices that can't
provide a MAC address until they are brought up, but we'll see.
Instead of requiring applets to hash passphrases, just do it in NM instead.
This should fix confusion where people don't understand that they are seeing
their hashed passphrase.
Use AC_GNU_SOURCE macro instead of setting -D_GNU_SOURCE manually.
The macro will add the _GNU_SOURCE define to config.h for systems that
have the GNU extensions.
