build: add `--without-tools` configure option

Change-Id: Idc10aea140c8863a23dccbb38be1b936d5d0302b
diff --git a/tools/wscript b/tools/wscript
index 0a13cad..9d198e7 100644
--- a/tools/wscript
+++ b/tools/wscript
@@ -5,18 +5,18 @@
 def build(bld):
     bld.program(
         name='ndncert-client',
-        target='../bin/ndncert-client',
+        target=f'{top}/bin/ndncert-client',
         source='ndncert-client.cpp',
-        use='ndn-cert')
+        use='libndn-cert')
 
     bld.program(
         name='ndncert-ca-server',
-        target='../bin/ndncert-ca-server',
+        target=f'{top}/bin/ndncert-ca-server',
         source='ndncert-ca-server.cpp',
-        use='ndn-cert')
+        use='libndn-cert')
 
     bld.program(
         name='ndncert-ca-status',
-        target='../bin/ndncert-ca-status',
+        target=f'{top}/bin/ndncert-ca-status',
         source='ndncert-ca-status.cpp',
-        use='ndn-cert')
+        use='libndn-cert')