Couldn't figure out how to attach the patch, including inline:

Index: ext/mozembed/README
===================================================================
RCS file: /repository/php-gtk/ext/mozembed/README,v
retrieving revision 1.2
diff -u -8 -p -r1.2 README
--- ext/mozembed/README	22 Jun 2006 03:11:13 -0000	1.2
+++ ext/mozembed/README	4 May 2008 22:32:47 -0000
@@ -1,11 +1,11 @@
 LICENSE: Mozilla Public License / (Optionally LGPL/GPL)
 AUTHOR: Mozilla.org
 URL: http://lxr.mozilla.org/mozilla/source/embedding/browser/gtk/src/
 
 GtkMozembed is a widget that allows you to embed the Mozilla engine in your Gtk+
 applications. Check the demos/ directory for sample script(s).
 
-You need to add the --enable-mozembed switch to your ./configure statement when
+You need to add the --with-mozembed switch to your ./configure statement when
 you build PHP-GTK 2 in order to enable this extension.
 
 NOTE: This extension is currently supported only on the *nix platform.
Index: ext/mozembed/config.m4
===================================================================
RCS file: /repository/php-gtk/ext/mozembed/config.m4,v
retrieving revision 1.3
diff -u -8 -p -r1.3 config.m4
--- ext/mozembed/config.m4	28 May 2007 23:53:33 -0000	1.3
+++ ext/mozembed/config.m4	4 May 2008 22:32:47 -0000
@@ -1,27 +1,32 @@
 dnl $Id: config.m4,v 1.3 2007/05/28 23:53:33 anant Exp $
 dnl config.m4 for mozembed module
 
 define(firefox_required_version, 1.5.0)
 define(mozilla_required_version, 1.7.0)
+define(xulrunner_required_version, 1.7.0) #Just a wild guess
 
 PHP_GTK_ARG_WITH(mozembed,for GtkMozEmbed support,
 [  --with-mozembed         Enable GtkMozEmbed support],no)
 
 dnl first check for firefox, then mozilla
 if test "$PHP_GTK_MOZEMBED" != "no"; then
   PKG_CHECK_MODULES(MOZEMBED, [firefox-gtkmozembed >= firefox_required_version],
   have_mozembed=yes, have_mozembed=no)
   if test "$have_mozembed" != "yes"; then
     PKG_CHECK_MODULES(MOZEMBED, [mozilla-gtkmozembed >= mozilla_required_version],
     have_mozembed=yes, have_mozembed=no)
   fi
   if test "$have_mozembed" != "yes"; then
-    AC_MSG_RESULT([Unable to locate firefox-gtkmozembed version firefox_required_version or mozilla-gtkmozembed version mozilla_required_version or higher: not building])
+    PKG_CHECK_MODULES(MOZEMBED, [xulrunner-gtkmozembed >= xulrunner_required_version],
+    have_mozembed=yes, have_mozembed=no)
+  fi
+  if test "$have_mozembed" != "yes"; then
+    AC_MSG_RESULT([Unable to locate firefox-gtkmozembed version firefox_required_version, mozilla-gtkmozembed version mozilla_required_version, xulrunner-gtkmozembed xulrunner_required_version or higher: not building])
   else
     AC_DEFINE(HAVE_MOZEMBED, 1, [mozembed support])
     PHP_EVAL_INCLINE($MOZEMBED_CFLAGS)
     if test "$php_gtk_ext_shared" = "yes"; then
       PHP_EVAL_LIBLINE($MOZEMBED_LIBS, MOZEMBED_SHARED_LIBADD)
       PHP_SUBST(MOZEMBED_SHARED_LIBADD)
     else
       PHP_EVAL_LIBLINE($MOZEMBED_LIBS, PHP_GTK2_SHARED_LIBADD)

The system added new lines, messing up the patch. It can be downloaded at http://pastebin.com/pastebin.php?dl=f60e601e7

patch applied, i had to manually merge the m4 part.