The big problem with making an OS X application out of a GTK program
is that it won't start unless DYLD_LIBRARY_PATH and several other
environment variables point at all the GTK machinery. So your app
bundle has to contain two programs: a launcher to set up that
environment, and then the real main program that the launcher execs
once it's done so.
But in our case, we also need pterm to start subprocesses _without_
all that stuff in the environment - so our launcher has to be more
complicated than the usual one, because it's also got to save every
detail of how the environment was when it started up. So this is the
launcher program I'm going to use. Comments in the header explain in
more detail how it'll work.
Also in this commit, I add the other end of the same machinery to
gtkapp.c and uxpty.c: the former catches an extra command-line
argument that the launcher used to indicate how it had munged the
environment, and stores it in a global variable where the latter can
pick it up after fork() and use to actually undo the munging.
When it's finished, this will be the backbone of the OS X GTK port:
using a GtkApplication automatically gives us a properly OS X
integrated menu bar.
Using this source file in place of gtkmain.c turns the usual Unix
single-session-per-process PuTTY or pterm into the multi-session-per-
process OS X style one.
Things like Duplicate Session can be done much more simply here - we
just grab the Conf * from the source window and launch a new window
using it, with no fiddly interprocess work needed.
This is still experimental and has a lot of holes, but it's usable
enough to test and improve.
