[gnome-session] Check stricter for presence of xtrans (with option to disable)

[Dominique Leuenberger <dleuen src gnome org>]

commit aa4c9d125012ae94154ce075d62342b63b41a7d9
Author: Dominique Leuenberger <dimstar opensuse org>
Date:   Tue Feb 25 19:28:16 2014 +0100

    Check stricter for presence of xtrans (with option to disable)
    
    Not having xtrans available during build results in gnome-sessions
    listening on remote TCP sockets (although not acting upon them).
    
    We strongly encourage the use of xtrans to minimize this surface. If
    using xtrans is not an option, it can be overruled by --without-xtrans.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725100

 configure.ac                    |   16 +++++++++++-----
 gnome-session/gsm-xsmp-server.c |    8 ++++----
 2 files changed, 15 insertions(+), 9 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b6b2ac7..cfef3e4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -267,12 +267,18 @@ fi
 AC_SUBST(EXECINFO_LIBS)
 
 dnl ====================================================================
-dnl Check for newish X interface
+dnl Check for X transport interface - allows to disable ICE Transports
+dnl See also https://bugzilla.gnome.org/show_bug.cgi?id=725100
 dnl ====================================================================
-oCFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS $X_CFLAGS"
-AC_CHECK_HEADERS(X11/Xtrans/Xtrans.h)
-CFLAGS="$oCFLAGS"
+AC_ARG_WITH([xtrans],
+           [AS_HELP_STRING([--without-xtrans],
+                          [Build without xtrans support (results in ICE listening on remote TCP ports)])],
+           [],
+           [with_xtrans=yes])
+AS_IF([test "$with_xtrans" != "no"],
+      [PKG_CHECK_MODULES(XTRANS, xtrans,
+      [AC_DEFINE(HAVE_XTRANS, 1, [Have the X Transport library])])])
+AC_SUBST(HAVE_XTRANS)
 
 dnl ====================================================================
 dnl Code for checking whether IPv6 is enabled on the system....
diff --git a/gnome-session/gsm-xsmp-server.c b/gnome-session/gsm-xsmp-server.c
index 614c2d2..1460a28 100644
--- a/gnome-session/gsm-xsmp-server.c
+++ b/gnome-session/gsm-xsmp-server.c
@@ -39,14 +39,14 @@
 #include <X11/ICE/ICEconn.h>
 #include <X11/SM/SMlib.h>
 
-#ifdef HAVE_X11_XTRANS_XTRANS_H
+#if HAVE_XTRANS
 /* Get the proto for _IceTransNoListen */
 #define ICE_t
 #define TRANS_SERVER
 #include <X11/Xtrans/Xtrans.h>
 #undef  ICE_t
 #undef TRANS_SERVER
-#endif /* HAVE_X11_XTRANS_XTRANS_H */
+#endif /* HAVE_XTRANS */
 
 #include "gsm-xsmp-server.h"
 #include "gsm-xsmp-client.h"
@@ -582,7 +582,7 @@ setup_listener (GsmXsmpServer *server)
                 gsm_util_init_error (TRUE, "Could not initialize libSM: %s", error);
         }
 
-#ifdef HAVE_X11_XTRANS_XTRANS_H
+#if HAVE_XTRANS
         /* By default, IceListenForConnections will open one socket for each
          * transport type known to X. We don't want connections from remote
          * hosts, so for security reasons it would be best if ICE didn't
@@ -634,7 +634,7 @@ setup_listener (GsmXsmpServer *server)
                 gsm_util_init_error (TRUE, "IceListenForConnections did not return a local listener!");
         }
 
-#ifdef HAVE_X11_XTRANS_XTRANS_H
+#ifdef HAVE_XTRANS
         if (server->priv->num_local_xsmp_sockets != server->priv->num_xsmp_sockets) {
                 /* Xtrans was apparently compiled with support for some
                  * non-local transport besides TCP (which we disabled above); we