Clarify difference between sources and distribution archive
In the install instructions, explain that the distribution archive
contains more files than a checkout of the source tree. It is a common
mistake to believe that using a checkout of the source tree is equivalent
to downloading a distribution archive.
@@ -14,6 +14,9 @@ title: Compile Bazel from Source
[release page](https://github.com/bazelbuild/bazel/releases) for the desired
version. We recommend to also verify the signature made by our
[release key](https://bazel.build/bazel-release.pub.gpg) 48457EE0.
+ The distribution archive also contains generated files in addition to the
+ versioned sources, so this step _cannot_ be short cut by using a checkout
+ of the source tree.
3. Unzip the archive and call `bash ./compile.sh`; this will create a bazel
binary in `output/bazel`. This binary is self-contained, so it can be copied
