tools/perf: Fix static build of perf tool

tools/perf: Fix static build of perf tool

To build a statically linked version of the perf tool all needed
libraries must be added in the correct order to get the symbols
resolved. Currently this is broken when, e.g. python or newt
support is enabled -- libpython needs libpthread which is an
unconditional link dependency of the perf tool; libslang needs
libm, another unconditional dependency. To solve the problem in
the long run without the need to keep track of transitive
library dependencies, simply make the linker look at the EXTLIBS
multiple times until it has all symbols resolved.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/1308171818-20370-1-git-send-email-minipli@googlemail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>