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 <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: André Goddard Rosa <[e-mail]>
Cc: Clark Williams <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Fixes: 7bd330de43fd ("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 <[e-mail]>

tools/objtool/Build

···
 objtool-y += objtool.o
 
 objtool-y += libstring.o
+objtool-y += libctype.o
 objtool-y += str_error_r.o
 
 CFLAGS += -I$(srctree)/tools/lib
 
 $(OUTPUT)libstring.o: ../lib/string.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_o_c)
+
+$(OUTPUT)libctype.o: ../lib/ctype.c FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,cc_o_c)