Turn off building gtk-docs API reference

Building it fails starting with gtk-doc-1.22, and there have been
lots of validity errors with previous versions for some time. Until
someone comes and fixes it, stop building it.

configure.ac.in

@@ -180,22 +180,11 @@ dnl **************************************
 XDT_CHECK_OPTIONAL_PACKAGE([LIBNOTIFY], [libnotify], [0.4.0], [notifications],
                            [Mount notification support], [yes])
 
-dnl *************************
-dnl *** Check for gtk-doc ***
-dnl *************************
-GTK_DOC_CHECK([1.0])
-
 dnl ***********************************
 dnl *** Check for debugging support ***
 dnl ***********************************
 XDT_FEATURE_DEBUG([thunar_debug_default])
 
-dnl *************************************
-dnl *** Compensate for broken gtk-doc ***
-dnl *************************************
-XDT_SUPPORTED_FLAGS([GTK_DOC_EXTRA_CFLAGS], [-Wno-sign-compare])
-AC_SUBST([GTK_DOC_EXTRA_CFLAGS])
-
 dnl **************************************
 dnl *** Check for linker optimizations ***
 dnl **************************************
@@ -233,9 +222,6 @@ Makefile
 docs/Makefile
 docs/design/Makefile
 docs/papers/Makefile
-docs/reference/Makefile
-docs/reference/thunarx/Makefile
-docs/reference/thunarx/version.xml
 examples/Makefile
 examples/tex-open-terminal/Makefile
 icons/Makefile

docs/Makefile.am

-# $Id$
-
 SUBDIRS =								\
 	design								\
-	papers								\
-	reference
+	papers
 
 doc_DATA =								\
 	README.gtkrc