bug#14282: 24.3; gud-gdb doesn't work

[weijie sun]

When I debug C/C++ program using gdb, the gud-gdb never returns from
"scanf". When debugging programs without using "scanf", the debugger
works ok. And when I use gdb directly in the terminal(my terminal is
xfce-terminal), it works ok too.

When starting emacs from "emacs -Q", the problem still exists.

My distribution is ArchLinux, and the desktop environment is Xfce. I get
my emacs from the pacman.


In GNU Emacs 24.3.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.6.4)
of 2013-03-19 on eric
Windowing system distributor `The X.Org Foundation', version 11.0.11400000
Configured using:
`configure '--prefix=/usr' '--sysconfdir=/etc' '--libexecdir=/usr/lib'
'--localstatedir=/var' '--with-x-toolkit=gtk3' '--with-xft'
'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector
--param=ssp-buffer-size=4 -D_FORTIFY_SOURCE=2'
'LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro''

Important settings:
value of $LC_CTYPE: zh_CN.utf8
value of $LANG: zh_CN.utf8
value of $XMODIFIERS: @im=fcitx
locale-coding-system: utf-8-unix
default enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
global-auto-complete-mode: t
tooltip-mode: t
mouse-wheel-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
blink-cursor-mode: t
auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
buffer-read-only: t
line-number-mode: t
transient-mark-mode: t

Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <down> <down> <down> <down> <down> <down>
<down> <down> <down> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo>
<menu-bar> <help-menu> <send-emacs-bug-report>

Recent messages:
Loading dired-x...done
`flet' is an obsolete macro (as of 24.3); use either `cl-flet' or 
`cl-letf'.
Loading 
/home/sun/.emacs.d/el-get/color-theme/themes/color-theme-example.el 
(source)...done
Loading 
/home/sun/.emacs.d/el-get/color-theme/themes/color-theme-library.el 
(source)...done
`flet' is an obsolete macro (as of 24.3); use either `cl-flet' or 
`cl-letf'.
Loading /home/sun/.emacs.d/el-get/color-theme/deepblue-color-theme.el 
(source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
/home/sun/.emacs.d/el-get/el-get/.dir-locals hides 
/usr/share/emacs/24.3/lisp/gnus/.dir-locals

Features:
(shadow sort gnus-util mail-extr emacsbug message idna byte-opt
format-spec rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse
rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045
ietf-drums mm-util mail-prsvr mail-utils advice advice-preload
auto-complete-config auto-complete edmacro kmacro popup .loaddefs
color-theme wid-edit el-get el-get-autoloads el-get-list-packages
el-get-notify help-mode el-get-dependencies el-get-build el-get-status
pp el-get-recipes el-get-byte-compile el-get-methods el-get-fossil
el-get-svn el-get-pacman el-get-github-zip el-get-github-tar
el-get-http-zip el-get-http-tar el-get-hg el-get-git-svn el-get-fink
el-get-emacswiki el-get-http el-get-emacsmirror el-get-github el-get-git
el-get-elpa package cl-macs gv el-get-darcs el-get-cvs el-get-bzr
el-get-brew el-get-builtin el-get-apt-get el-get-custom el-get-core
autoload help-fns bytecomp byte-compile cconv cl cl-lib dired-x easymenu
dired ido time-date china-util tooltip ediff-hook vc-hooks
lisp-float-type mwheel x-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment lisp-mode register page menu-bar
rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak
czech european ethiopic indian cyrillic chinese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer loaddefs button faces
cus-face macroexp files text-properties overlay sha1 md5 base64 format
env code-pages mule custom widget hashtable-print-readable backquote
make-network-process dbusbind dynamic-setting system-font-setting
font-render-setting move-toolbar gtk x-toolkit x multi-tty emacs)