Small corrections

Co-Authored-By: Ralf Jung <post@ralfj.de>

Author: pvdrz

README.md

@@ -161,7 +161,7 @@ Several `-Z` flags are relevant for Miri:
   the program has access to host resources such as environment variables and
   randomness (and, eventually, file systems and more).
 * `-Zmiri-env-exclude=<var>` keeps the `var` environment variable isolated from 
-  the host. It can be used multiple times to exclude several variables.
+  the host. Can be used multiple times to exclude several variables.
 * `-Zmir-opt-level` controls how many MIR optimizations are performed.  Miri
   overrides the default to be `0`; be advised that using any higher level can
   make Miri miss bugs in your program because they got optimized away.

benches/helpers/miri_helper.rs

@@ -28,6 +28,7 @@ impl rustc_driver::Callbacks for MiriCompilerCalls<'_> {
                 let config = miri::MiriConfig {
                     validate: true,
                     communicate: false,
+                    excluded_env_vars: vec![],
                     args: vec![],
                     seed: None,
                 };

src/bin/miri-rustc-tests.rs

@@ -70,6 +70,7 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
                 let config = MiriConfig {
                     validate: true,
                     communicate: false,
+                    excluded_env_vars: vec![],
                     args: vec![],
                     seed: None
                 };

src/eval.rs

@@ -24,6 +24,7 @@ pub struct MiriConfig {
     pub communicate: bool,
     /// Environment variables that should always be isolated from the host.
     pub excluded_env_vars: Vec<String>,
+    /// Command-line arguments passed to the interpreted program.
     pub args: Vec<String>,
     /// The seed to use when non-determinism or randomness are required (e.g. ptr-to-int cast, `getrandom()`).
     pub seed: Option<u64>,