diff --git a/src/main.rs b/src/main.rs
index 954c265..973e331 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -176,13 +176,14 @@ fn do_main() -> Result<()> {
     }
 
     let mut rustflags = metadata.rustc_args.clone();
+    rustflags.insert(0, "--cfg=docsrs".to_owned());
     if let Some(encoded_rustflags) = env::var_os("CARGO_ENCODED_RUSTFLAGS") {
         if let Some(encoded_rustflags) = encoded_rustflags.to_str() {
-            rustflags.splice(0..0, encoded_rustflags.split('\x1f').map(str::to_owned));
+            rustflags.splice(1..1, encoded_rustflags.split('\x1f').map(str::to_owned));
         }
     } else if let Some(env_rustflags) = env::var_os("RUSTFLAGS") {
         if let Some(env_rustflags) = env_rustflags.to_str() {
-            rustflags.splice(0..0, env_rustflags.split_whitespace().map(str::to_owned));
+            rustflags.splice(1..1, env_rustflags.split_whitespace().map(str::to_owned));
         }
     }
 
@@ -199,14 +200,17 @@ fn do_main() -> Result<()> {
     ));
 
     let mut rustdocflags = metadata.rustdoc_args.clone();
-    rustdocflags.insert(0, "-Zunstable-options".to_owned());
+    rustdocflags.splice(
+        0..0,
+        ["-Zunstable-options".to_owned(), "--cfg=docsrs".to_owned()],
+    );
     if let Some(encoded_rustdocflags) = env::var_os("CARGO_ENCODED_RUSTDOCFLAGS") {
         if let Some(encoded_rustdocflags) = encoded_rustdocflags.to_str() {
-            rustdocflags.splice(1..1, encoded_rustdocflags.split('\x1f').map(str::to_owned));
+            rustdocflags.splice(2..2, encoded_rustdocflags.split('\x1f').map(str::to_owned));
         }
     } else if let Some(env_rustdocflags) = env::var_os("RUSTDOCFLAGS") {
         if let Some(env_rustdocflags) = env_rustdocflags.to_str() {
-            rustdocflags.splice(1..1, env_rustdocflags.split_whitespace().map(str::to_owned));
+            rustdocflags.splice(2..2, env_rustdocflags.split_whitespace().map(str::to_owned));
         }
     }
     rustdocflags.push("--extern-html-root-takes-precedence".to_owned());