build: align minimum build dependencies with ndn-cxx
* Recommend boost >= 1.65.1 and gcc >= 7.4.0
* Require clang >= 4.0, or Xcode >= 9.0 on macOS
* Silence an ABI-related diagnostic message from gcc on armv7
Refs: #5087, #5106
Change-Id: I88ef0e0f183736f19ac414a84baebb0e1073381b
diff --git a/README.md b/README.md
index daf3dde..b2b7a47 100644
--- a/README.md
+++ b/README.md
@@ -27,9 +27,9 @@
## Contributing
-You're encouraged to contribute to ndn-tools! If you are new to the NDN
+We greatly appreciate contributions to ndn-tools. If you are new to the NDN
software community, please read [`README-dev.md`](README-dev.md) and the
-[Contributor's Guide](https://github.com/named-data/NFD/blob/master/CONTRIBUTING.md)
+[Contributor's Guide](https://github.com/named-data/.github/blob/master/CONTRIBUTING.md)
to get started.
## License