Make dependency on GTK+ optional at compile time

[Aurélien Gâteau]

Source-based distribution packagers would like to be able to provide libindicate to users without forcing them to install GTK+ to build it.

[Dennis Schridde (devurandom)]

As GObject Introspection is somewhat broken, and even more so is the test using a non-existant macro in configure.ac, the following patch was also necessary. I do not consider it a solution of any kind, so it's not attached.
--- configure.ac.orig 2010-03-31 12:42:16.497596552 +0200
+++ configure.ac 2010-03-31 12:42:47.001595062 +0200
@@ -87,6 +87,6 @@
 ###########################

-GOBJECT_INTROSPECTION_CHECK([0.6.3])
+AM_CONDITIONAL([HAVE_INTROSPECTION], [false])

 ###########################
 # GTK Doc

[Dennis Schridde (devurandom)]

See bug #552537 for the GObject Introspection issue.

[Dennis Schridde (devurandom)]

Attached patch makes it possible to disable compilation of libindicate-gtk, but it fails if you build the python bindings, because they try to link against it.

So this depends on bug #643921, or needs some code modifications to exclude the gtk dependent stuff from the python bindings.

[Dennis Schridde (devurandom)]

Attached patch improves upon the last, mainly preserving order of SUBDIRS.

[Alex Launi (alexlauni)]

Could you please add some output to the configure to show whether not gtk support will be built?

[Dennis Schridde (devurandom)]

Improved patch with safer macro quoting and diagnostic output at the end of configure.