Auto merge of rust-lang#2546 - RalfJung:comments, r=RalfJung

add/fix some comments

Author: bors

src/eval.rs

@@ -295,7 +295,10 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
 
             let main_ptr = ecx.create_fn_alloc_ptr(FnVal::Instance(entry_instance));
 
-            let sigpipe = 2; // Inlining of `DEFAULT` from https://github.com/rust-lang/rust/blob/master/compiler/rustc_session/src/config/sigpipe.rs
+            // Inlining of `DEFAULT` from
+            // https://github.com/rust-lang/rust/blob/master/compiler/rustc_session/src/config/sigpipe.rs.
+            // Alaways using DEFAULT is okay since we don't support signals in Miri anyway.
+            let sigpipe = 2;
 
             ecx.call_function(
                 start_instance,

src/shims/windows/foreign_items.rs

@@ -294,8 +294,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 let flags = this.read_scalar(flags)?.to_u32()?;
                 match flags {
                     0 => {
-                        // BCRYPT_RNG_ALG_HANDLE
                         if algorithm != 0x81 {
+                            // BCRYPT_RNG_ALG_HANDLE
                             throw_unsup_format!(
                                 "BCryptGenRandom algorithm must be BCRYPT_RNG_ALG_HANDLE when the flag is 0"
                             );