Description of the problem / feature request:

Bazel 3.7.0 can't be compiled on Alpine linux; I get the following error:

$ wget https://github.com/bazelbuild/bazel/releases/download/3.7.0/bazel-3.7.0-dist.zip && unzip bazel-3.7.0-dist.zip
$ env EXTRA_BAZEL_ARGS="--host_javabase=@local_jdk//:jdk" bash ./compile.sh
Building Bazel from scratch......
Building Bazel with Bazel.
<snip>
    Compiling src/main/tools/linux-sandbox.cc; 0s local
src/main/tools/linux-sandbox-pid1.cc: In function 'int WaitForChild()':
src/main/tools/linux-sandbox-pid1.cc:402:23: error: 'TEMP_FAILURE_RETRY' was not declared in this scope
  402 |     const pid_t pid = TEMP_FAILURE_RETRY(wait(&status));
      |                       ^~~~~~~~~~~~~~~~~~

It seems that TEMP_FAILURE_RETRY is only available on GNU libc, where Alpine uses musl libc. The last Bazel version I tried on Alpine was 3.5.0 and that was compiling/running fine.

What operating system are you running Bazel on?

Alpine linux, 3.13.0_alpha20200917. Running within docker using the alpine:edge tag.

Have you found anything relevant by searching the web?

1. The line that errors was added in commit 1517af1.
2. I found a definition for TEMP_FAILURE_RETRY on StackOverflow that does seem to work (meaning, compilation succeeds) when added to the linux-sandbox-pid1.cc file, but this is not my area of expertise so I can't tell if it's actually doing what it's supposed to do, or if it just looks like it is.