run_binary does not include executable environment from RunEnvironmentInfo

[brett-patterson-ent]

If the tool provided to run_binary has a RunEnvironmentInfo provider, that environment is not included when running the tool. For example, this is how py_binary from rules_py sets provided environment variables.

This basic patch includes the environment and allows envs specified directly to run_binary to override the ones provided by the tool:

diff --git lib/private/run_binary.bzl lib/private/run_binary.bzl
index b480a27..9f12b21 100644
--- lib/private/run_binary.bzl
+++ lib/private/run_binary.bzl
@@ -51,6 +51,8 @@ Possible fixes:
     for a in ctx.attr.args:
         args.add_all(split_args(expand_variables(ctx, ctx.expand_location(a, targets = ctx.attr.srcs), inputs = ctx.files.srcs, outs = outputs)))
     envs = {}
+    if RunEnvironmentInfo in ctx.attr.tool:
+        envs = ctx.attr.tool[RunEnvironmentInfo].environment
     for k, v in ctx.attr.env.items():
         envs[k] = expand_variables(ctx, ctx.expand_location(v, targets = ctx.attr.srcs), inputs = ctx.files.srcs, outs = outputs, attribute_name = "env")

The patch is working for our use cases right now. Happy to submit it as a PR if the implementation seems generally correct.