Description of problem:
valgrind fails to start its tools (memcheck, cachegrind, helgrind) when it is
used to profile applications for PPC64 (e.g. 64-bit applications). Since
valgrind relies on these tools, the bug makes it practically useless.

The following error message is reported by valgrind while running it without any
option or argument:
$ valgrind name-of-application
valgrind: failed to start tool 'memcheck' for platform 'ppc64-linux': No such
file or directory

Version-Release number of selected component (if applicable):
* valgrind.ppc64 3.2.3-2
* valgrind.ppc 3.2.3-2   

How reproducible:
Always.

Steps to Reproduce:
1. Find or compile a PPC64 application. 
2. Try to profile the application with valgrind :
   $ valgrind name-of-program
  
Actual results:
valgrind cannot find the requested tool, thus failing to profile the application.

Expected results:
valgrind and its tools should profile applications correctly.

Additional info:
* valgrind works correctly with PPC32 applications.
* If you cannot find a PPC64 application, you can use valgrind on /lib64/libc.so.6 :
  $ valgrind /lib64/libc.so.6
* It seems to be a path issue. While running valgrind with the debug switch, it
tries to access an unexisting file :
  [paclb@ps3-gel01 celldt]$ valgrind -d /tmp/celldt/convofilter
  --26657:1:debuglog DebugLog system started by Stage 1, level 1 logging requested
  --26657:1:launcher no tool requested, defaulting to 'memcheck'
  --26657:1:launcher selected platform 'ppc64-linux'
  --26657:1:launcher launching /usr/lib/valgrind/ppc64-linux/memcheck
valgrind: failed to start tool 'memcheck' for platform 'ppc64-linux': No such
file or directory

  The directory /usr/lib/valgrind/ppc64-linux doesn't exist, but
/usr/lib64/valgrind/ppc64-linux does (and contains the requested tools).
* I have included an strace of the previous command.