Index: m4/gecko.m4
===================================================================
--- m4/gecko.m4	(revision 1668)
+++ m4/gecko.m4	(working copy)
@@ -51,7 +51,7 @@
 AC_MSG_CHECKING([which gecko to use])
 
 AC_ARG_WITH([gecko],
-	AS_HELP_STRING([--with-gecko@<:@=mozilla|firefox|seamonkey|xulrunner@:>@],
+	AS_HELP_STRING([--with-gecko@<:@=mozilla|firefox|seamonkey|xulrunner|libxul@:>@],
 		       [Which gecko engine to use (autodetected by default)]))
 
 # Backward compat
@@ -60,9 +60,13 @@
 gecko_cv_gecko=$with_gecko
 
 # Autodetect gecko
-_geckos="xulrunner firefox mozilla-firefox seamonkey mozilla"
+_geckos="xulrunner firefox mozilla-firefox seamonkey mozilla libxul"
 if test -z "$gecko_cv_gecko"; then
 	for lizard in $_geckos; do
+		if $PKG_CONFIG --exists $lizard-unstable; then
+			gecko_cv_gecko=$lizard
+			break;
+		fi
 		if $PKG_CONFIG --exists $lizard-xpcom; then
 			gecko_cv_gecko=$lizard
 			break;
@@ -93,12 +97,20 @@
 seamonkey) gecko_cv_gecko_flavour=mozilla ;;
 *firefox) gecko_cv_gecko_flavour=toolkit ;;
 xulrunner) gecko_cv_gecko_flavour=toolkit ;;
+libxul*) gecko_cv_gecko_flavour=toolkit ;;
 esac
 
+if test $gecko_cv_gecko = libxul; then
+_GECKO_INCLUDE_ROOT="`$PKG_CONFIG --variable=includedir ${gecko_cv_gecko}-unstable`/unstable"
+_GECKO_LIBDIR="`$PKG_CONFIG --variable=sdkdir ${gecko_cv_gecko}-unstable`/lib"
+_GECKO_HOME=""
+_GECKO_PREFIX="`$PKG_CONFIG --variable=prefix ${gecko_cv_gecko}-unstable`"
+else
 _GECKO_INCLUDE_ROOT="`$PKG_CONFIG --variable=includedir ${gecko_cv_gecko}-xpcom`"
 _GECKO_LIBDIR="`$PKG_CONFIG --variable=libdir ${gecko_cv_gecko}-xpcom`"
 _GECKO_HOME="`$PKG_CONFIG --variable=libdir ${gecko_cv_gecko}-xpcom`"
 _GECKO_PREFIX="`$PKG_CONFIG --variable=prefix ${gecko_cv_gecko}-xpcom`"
+fi
 
 fi # if gecko_cv_have_gecko
 
@@ -371,10 +383,17 @@
 _SAVE_CXXFLAGS="$CXXFLAGS"
 _SAVE_LDFLAGS="$LDFLAGS"
 _SAVE_LIBS="$LIBS"
+if test $gecko_cv_gecko = libxul; then
+CPPFLAGS="$CPPFLAGS $_GECKO_EXTRA_CPPFLAGS -I$_GECKO_INCLUDE_ROOT $($PKG_CONFIG --cflags-only-I ${gecko_cv_gecko}-unstable)"
+CXXFLAGS="$CXXFLAGS $_GECKO_EXTRA_CXXFLAGS $($PKG_CONFIG --cflags-only-other ${gecko_cv_gecko}-unstable)"
+LDFLAGS="$LDFLAGS $_GECKO_EXTRA_LDFLAGS"
+LIBS="$LIBS $($PKG_CONFIG --libs ${gecko_cv_gecko}-unstable)"
+else
 CPPFLAGS="$CPPFLAGS $_GECKO_EXTRA_CPPFLAGS -I$_GECKO_INCLUDE_ROOT $($PKG_CONFIG --cflags-only-I ${gecko_cv_gecko}-xpcom)"
 CXXFLAGS="$CXXFLAGS $_GECKO_EXTRA_CXXFLAGS $($PKG_CONFIG --cflags-only-other ${gecko_cv_gecko}-xpcom)"
 LDFLAGS="$LDFLAGS $_GECKO_EXTRA_LDFLAGS -Wl,--rpath=$_GECKO_HOME"
 LIBS="$LIBS $($PKG_CONFIG --libs ${gecko_cv_gecko}-xpcom)"
+fi
 
 _GECKO_DISPATCH_INCLUDEDIRS="$2"
 
@@ -607,11 +626,19 @@
 AC_DEFUN([GECKO_XPIDL],
 [AC_REQUIRE([GECKO_INIT])dnl
 
+if test $gecko_cv_gecko = libxul; then
 _GECKO_LIBDIR="`$PKG_CONFIG --variable=libdir ${gecko_cv_gecko}-xpcom`"
+else
+_GECKO_LIBDIR="`$PKG_CONFIG --variable=sdkdir ${gecko_cv_gecko}-unstable`/lib"
+fi
 
 AC_PATH_PROG([XPIDL],[xpidl],[no],[$_GECKO_LIBDIR:$PATH])
 
+if test $gecko_cv_gecko = libxul; then
+XPIDL_IDLDIR="`$PKG_CONFIG --variable=idldir ${gecko_cv_gecko}-unstable`/unstable"
+else
 XPIDL_IDLDIR="`$PKG_CONFIG --variable=idldir ${gecko_cv_gecko}-xpcom`"
+fi
 
 # Older geckos don't have this variable, see
 # https://bugzilla.mozilla.org/show_bug.cgi?id=240473
Index: extensions/error-viewer/mozilla/mozilla-link-checker.cpp
===================================================================
--- extensions/error-viewer/mozilla/mozilla-link-checker.cpp	(revision 1668)
+++ extensions/error-viewer/mozilla/mozilla-link-checker.cpp	(working copy)
@@ -21,8 +21,8 @@
 #include "mozilla-config.h"
 #include "config.h"
 
-#include <gtkembedmoz/gtkmozembed.h>
-#include <gtkembedmoz/gtkmozembed_internal.h>
+#include <gtkmozembed.h>
+#include <gtkmozembed_internal.h>
 #include <nsAutoPtr.h>
 #include <nsCOMPtr.h>
 #include <nsComponentManagerUtils.h>
Index: configure.ac
===================================================================
--- configure.ac	(revision 1668)
+++ configure.ac	(working copy)
@@ -324,10 +324,15 @@
 case "$MOZILLA" in
 xulrunner) min_version=1.8 ;;
 *firefox) min_version=1.5 ;;
+libxul) min_version=1.9 ;;
 *) AC_MSG_ERROR([Unsupported gecko "$gecko_cv_gecko"]) ;;
 esac
 
+if test $MOZILLA = libxul; then
+PKG_CHECK_MODULES([MOZILLA_COMPONENT],[${gecko_cv_gecko}-unstable >= $min_version $gecko_cv_extra_pkg_dependencies])
+else
 PKG_CHECK_MODULES([MOZILLA_COMPONENT],[${gecko_cv_gecko}-xpcom >= $min_version $gecko_cv_extra_pkg_dependencies])
+fi
 AC_SUBST([MOZILLA_COMPONENT_CFLAGS])
 AC_SUBST([MOZILLA_COMPONENT_LIBS])