From 5b2f8789b2a0027df52cdb8e98f8c0915d84fced Mon Sep 17 00:00:00 2001
From: Peter Huene <peter@huene.dev>
Date: Wed, 10 Feb 2021 23:04:04 -0800
Subject: [PATCH] Allow zero-sized allocations on Windows for `Mmap`.

---
 crates/runtime/src/mmap.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/crates/runtime/src/mmap.rs b/crates/runtime/src/mmap.rs
index 61ccda9276..e60e87e378 100644
--- a/crates/runtime/src/mmap.rs
+++ b/crates/runtime/src/mmap.rs
@@ -124,6 +124,10 @@ impl Mmap {
         use winapi::um::memoryapi::VirtualAlloc;
         use winapi::um::winnt::{MEM_COMMIT, MEM_RESERVE, PAGE_NOACCESS, PAGE_READWRITE};
 
+        if mapping_size == 0 {
+            return Ok(Self::new());
+        }
+
         let page_size = region::page::size();
         assert_le!(accessible_size, mapping_size);
         assert_eq!(mapping_size & (page_size - 1), 0);