Support for z80(sdcc) port.

In order to support, some core modules are modified as follows:

core/sys/dsc.h
- If CTK_CONF_ICONS is diabled, the whole icon-related code is disabled.
- DSC_HEADER is changed to remove extra semicolon.

core/sys/process.h
- process_data_t is expressed by void* in signatures (known bug on sdcc).

core/sys/autostart.h
- autostart_processes is changed to remove extra semicolon.

core/sys/cc.h
- CC_CONF_ASSIGN_AGGREGATE is introduced.
- CC_CONF_INC_CAST_POINTER is introduced, a workaround of a kind
  of sdcc bug for an increment.

core/net/hc.c
core/net/uip_arp.c
core/net/uaodv.c
- Aggregation assignments are changed to uip_ipaddr_copy.

core/net/psock.c
core/net/uipbuf.c
core/net/dhcpc.c
apps/shell/shell.c
core/ctk/vnc-server.c
core/ctk/vnc-out.c
- "register" keyword in a signature cannot be used in sdcc,
  CC_REGISTER_ARG is used instead.

core/net/uip-over-mesh.c
- An extra semicolon is removed.

apps/dhcp/dhcp-dsc.c
apps/shell/shell-dsc.
apps/ftp/ftp-dsc.c
apps/process-list/process-list-dsc.c
apps/email/email-dsc.c
apps/webserver/webserver-dsc.c
apps/vnc/vnc-dsc.c
apps/vnc/vnc-viewer.h
apps/webbrowser/www-dsc.c
apps/about/about-dsc.c
apps/irc/irc-dsc.c
apps/telnet/telnet-dsc.c
apps/telnetd/telnetd-dsc.c
apps/netconf/netconf-dsc.c
apps/directory/directory-dsc.c
pps/calc/calc-dsc.c
- Modify an extern type to a real declaration, which is static
  to prevent a compile error.

core/net/mac/xmac.c
- Variables cannot be defined in a head of block on sdcc.

core/ctk/ctk.h
core/ctk/ctk.c
apps/program-handler/program-handler.c
- If CTK_CONF_ICONS is diabled, the whole icon-related code is disabled.

Makefile.include
- Add a set of configuration for an assembler.
- $(CLEAN) variable is introduced for customized cleanup.

apps/process-list/process-list.c
- PROCESSLIST_CONF_HEIGHT is introduced to address smaller screen size.

core/lib/ctk-filedialog.c
- FILES_CONF_HEIGHT is introduced to address smaller screen size.
- "register" keyword in a signature cannot be used in sdcc,
  CC_REGISTER_ARG is used instead.

apps/vnc/vnc-viewer.c
- A cast is added to prevent a compile error.
- "register" keyword in a signature cannot be used in sdcc,
  CC_REGISTER_ARG is used instead.

apps/webbrowser/webclient.c
- CC_CONF_INC_CAST_POINTER is introduced, a workaround of a kind
  of sdcc bug for an increment.

core/loader/elfloader.c
- A cast is added to prevent a compile error.

core/net/rime/rimeaddr.c
- An initialization is added to prevent a compile error.

core/net/rime/rudolph0.c
- NULL is changed to 0, because NULL causes a compile error.

core/net/rime/route-discovery.c
- Add an argument to match the definition of nf_callbacks.

cpu/z80/strcasecmp.h
cpu/z80/strcasecmp.c
cpu/z80/contiki-sdcc-conf.h
cpu/z80/mtarch.c
cpu/z80/mtarch.h
cpu/z80/Makefile.z80
- New files to make compilation availble on sdcc.
- Added support for multithreading.

apps/shell/shell.c

@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki desktop OS.
  *
- * $Id: shell.c,v 1.4 2007/04/14 08:11:24 oliverschmidt Exp $
+ * $Id: shell.c,v 1.5 2007/08/30 14:39:16 matsutsuka Exp $
  *
  */
 
@@ -52,7 +52,7 @@ struct ptentry {
 
 /*-----------------------------------------------------------------------------------*/
 static void
-parse(register char *str, struct ptentry *t)
+parse(CC_REGISTER_ARG char *str, struct ptentry *t)
 {
   register struct ptentry *p;
   char *sstr;
@@ -85,7 +85,7 @@ parse(register char *str, struct ptentry *t)
 }
 /*-----------------------------------------------------------------------------------*/
 static void
-inttostr(register char *str, unsigned int i)
+inttostr(CC_REGISTER_ARG char *str, unsigned int i)
 {
   str[0] = '0' + i / 100;
   if(str[0] == '0') {