$ pacman -S xfce4 xfce4-goodies
:: group xfce4:
    exo gtk-xfce-engine libxfce4mcs libxfce4util libxfcegui4 mousepad terminal thunar xfce-mcs-manager xfce-mcs-plugins
    xfce-utils xfce4-appfinder xfce4-icon-theme xfce4-mixer xfce4-panel xfce4-session xfdesktop xfprint xfwm4 xfwm4-themes
:: Install whole content? [Y/n]
memory clobbered before allocated block
Aborted

$ sudo gdb /usr/bin/pacman3
GNU gdb 6.6
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...
(no debugging symbols found)
Using host libthread_db library "/lib/libthread_db.so.1".
(gdb) run -S xfce4 xfce4-goodies
Starting program: /usr/bin/pacman3 -S xfce4 xfce4-goodies
(no debugging symbols found)
Failed to read a valid object file image from memory.
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
:: group xfce4:
    exo gtk-xfce-engine libxfce4mcs libxfce4util libxfcegui4 mousepad terminal thunar xfce-mcs-manager xfce-mcs-plugins
    xfce-utils xfce4-appfinder xfce4-icon-theme xfce4-mixer xfce4-panel xfce4-session xfdesktop xfprint xfwm4 xfwm4-themes
:: Install whole content? [Y/n]
memory clobbered before allocated block

Program received signal SIGABRT, Aborted.
0xb7ef8410 in ?? ()
(gdb) bt
#0  0xb7ef8410 in ?? ()
#1  0xbfd50bfc in ?? ()
#2  0x00000006 in ?? ()
#3  0x00003215 in ?? ()
#4  0xb7d39721 in raise () from /lib/libc.so.6
#5  0xb7d3aef8 in abort () from /lib/libc.so.6
#6  0xb7d6ee6b in __libc_message () from /lib/libc.so.6
#7  0xb7d6efa4 in __libc_fatal () from /lib/libc.so.6
#8  0xb7d79bf7 in mabort () from /lib/libc.so.6
#9  0xb7d794f4 in checkhdr () from /lib/libc.so.6
#10 0xb7e36ff4 in ?? () from /lib/libc.so.6
#11 0x0824eaf0 in ?? ()
#12 0xbfd5130c in ?? ()
#13 0xb7d79885 in freehook () from /lib/libc.so.6
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb)