objtool: Fix build by linking against tools/lib/ctype.o sources

Fix objtool build, because it adds _ctype dependency via isspace call patch.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 7bd330de ("tools lib: Adopt skip_spaces() from the kernel sources")
Link: http://lkml.kernel.org/r/20190702121240.GB12694@krava


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>