diff --git a/cli/build.rs b/cli/build.rs
index 35fadfa642..84c74683d9 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -200,8 +200,8 @@ fn git_commit_hash() -> String {
 }
 
 fn main() {
-  // Don't build V8 if "cargo doc" is being run. This is to support docs.rs.
-  if env::var_os("RUSTDOCFLAGS").is_some() {
+  // Skip building from docs.rs.
+  if env::var_os("DOCS_RS").is_some() {
     return;
   }
 
diff --git a/runtime/build.rs b/runtime/build.rs
index e8f036eff7..3b8be41367 100644
--- a/runtime/build.rs
+++ b/runtime/build.rs
@@ -8,8 +8,8 @@ use std::env;
 use std::path::PathBuf;
 
 fn main() {
-  // Don't build V8 if "cargo doc" is being run. This is to support docs.rs.
-  if env::var_os("RUSTDOCFLAGS").is_some() {
+  // Skip building from docs.rs.
+  if env::var_os("DOCS_RS").is_some() {
     return;
   }