[PATCH] Fix menuconfig build failure due to missing stdbool.h

[PATCH] Fix menuconfig build failure due to missing stdbool.h

scripts/kconfig/lxdialog/util.c fails to build because it uses
true/false without including stdbool.h:

kronos:~/src/linux-2.6$ make O=../linux-build-git menuconfig
  GEN     /home/kronos/src/linux-build/Makefile
  HOSTCC  scripts/kconfig/lxdialog/util.o
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c: In function 'set_classic_theme':
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:68: error: 'true' undeclared (first use in this function)
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:68: error: (Each undeclared identifier is reported only once
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:68: error: for each function it appears in.)
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:70: error: 'false' undeclared (first use in this function)
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c: In function 'set_blackbg_theme':
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:101: error: 'true' undeclared (first use in this function)
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:102: error: 'false' undeclared (first use in this function)
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c: In function 'set_bluetitle_theme':
/home/kronos/src/linux-2.6/scripts/kconfig/lxdialog/util.c:144: error: 'true' undeclared (first use in this function)
make[2]: *** [scripts/kconfig/lxdialog/util.o] Error 1
make[1]: *** [menuconfig] Error 2
make: *** [menuconfig] Error 2

Add <stdbool.h> to dialog.h to fix the breakage.

Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>