um: xterm: Make default terminal emulator configurable

Make the default terminal emulator configurable so e.g.
Debian can set it to x-terminal-emulator instead of the
current default of xterm.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Tested-by: Ritesh Raj Sarraf <ritesh@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/drivers/Kconfig

@@ -64,6 +64,13 @@ config XTERM_CHAN
 	  its own xterm.
 	  It is safe to say 'Y' here.
 
+config XTERM_CHAN_DEFAULT_EMULATOR
+	string "xterm channel default terminal emulator"
+	depends on XTERM_CHAN
+	default "xterm"
+	help
+	  This option allows changing the default terminal emulator.
+
 config NOCONFIG_CHAN
 	bool
 	default !(XTERM_CHAN && TTY_CHAN && PTY_CHAN && PORT_CHAN && NULL_CHAN)

arch/um/drivers/Makefile

@@ -70,4 +70,6 @@ obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o
 USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o pcap_user.o vde_user.o vector_user.o
 CFLAGS_null.o = -DDEV_NULL=$(DEV_NULL_PATH)
 
+CFLAGS_xterm.o += '-DCONFIG_XTERM_CHAN_DEFAULT_EMULATOR="$(CONFIG_XTERM_CHAN_DEFAULT_EMULATOR)"'
+
 include arch/um/scripts/Makefile.rules

arch/um/drivers/xterm.c

@@ -42,7 +42,7 @@ static void *xterm_init(char *str, int device, const struct chan_opts *opts)
 }
 
 /* Only changed by xterm_setup, which is a setup */
-static char *terminal_emulator = "xterm";
+static char *terminal_emulator = CONFIG_XTERM_CHAN_DEFAULT_EMULATOR;
 static char *title_switch = "-T";
 static char *exec_switch = "-e";
 
@@ -79,8 +79,9 @@ __uml_setup("xterm=", xterm_setup,
 "    respectively.  The title switch must have the form '<switch> title',\n"
 "    not '<switch>=title'.  Similarly, the exec switch must have the form\n"
 "    '<switch> command arg1 arg2 ...'.\n"
-"    The default values are 'xterm=xterm,-T,-e'.  Values for gnome-terminal\n"
-"    are 'xterm=gnome-terminal,-t,-x'.\n\n"
+"    The default values are 'xterm=" CONFIG_XTERM_CHAN_DEFAULT_EMULATOR
+     ",-T,-e'.\n"
+"    Values for gnome-terminal are 'xterm=gnome-terminal,-t,-x'.\n\n"
 );
 
 static int xterm_open(int input, int output, int primary, void *d,