diff --git a/tools/objtool/Build b/tools/objtool/Build
index 749becdf5b9080a1c3189d7d4972f9952cb200e5..8dc4f0848362d2964ed2f7b64cc09a7a84f58a83 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -9,6 +9,7 @@ objtool-y += special.o
 objtool-y += objtool.o
 
 objtool-y += libstring.o
+objtool-y += libctype.o
 objtool-y += str_error_r.o
 
 CFLAGS += -I$(srctree)/tools/lib
@@ -17,6 +18,10 @@ $(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)
+
 $(OUTPUT)str_error_r.o: ../lib/str_error_r.c FORCE
 	$(call rule_mkdir)
 	$(call if_changed_dep,cc_o_c)