perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable

perf tools: Move libtraceevent dynamic list to separated LDFLAGS variable

Commit e3d09ec8126fe2c9a3ade661e2126e215ca27a80 ("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 <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>