perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable

perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable

Commit 532a0ce20445fa0dfe7feab8ffce0fb29d43d2d6 ("tools lib traceevent:
Export dynamic symbols used by traceevent plugins") adds libtraceevent
dynamic list directly into LDFLAGS, which makes all targets depend on
that list through LDFLAGS.

This is not good since some of targets like libgtk.so doesn't use plugin
at all, but require the existance of that list because of linker
options.

This patch isolates the -Xlink option into LIBTRACEEVENT_DYNAMIC_LIST_LDFLAGS,
makes only perf and perf.so use it.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1434552389-89144-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>