crates/rustversion/patches/version.diff

diff --git a/src/expand.rs b/src/expand.rs
index 813ba85d7..3d4e31485 100644
--- a/src/expand.rs
+++ b/src/expand.rs
@@ -23,7 +23,7 @@ fn try_cfg(introducer: &str, args: TokenStream, input: TokenStream) -> Result<To
     let expr = expr::parse(full_args)?;
     token::parse_end(full_args)?;
 
-    if expr.eval(crate::RUSTVERSION) {
+    if expr.eval(crate::rust_version()) {
         Ok(allow_incompatible_msrv(input))
     } else {
         Ok(TokenStream::new())
@@ -31,7 +31,7 @@ fn try_cfg(introducer: &str, args: TokenStream, input: TokenStream) -> Result<To
 }
 
 pub fn try_attr(args: attr::Args, input: TokenStream) -> Result<TokenStream> {
-    if !args.condition.eval(crate::RUSTVERSION) {
+    if !args.condition.eval(crate::rust_version()) {
         return Ok(input);
     }
 
diff --git a/src/lib.rs b/src/lib.rs
index 96e70c0b5..866153b82 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -213,12 +213,32 @@ use crate::error::Error;
 use crate::version::Version;
 use proc_macro::TokenStream;
 
-#[cfg(not(host_os = "windows"))]
+#[cfg(all(not(host_os = "windows"), not(soong), not(trusty)))]
 const RUSTVERSION: Version = include!(concat!(env!("OUT_DIR"), "/version.expr"));
 
-#[cfg(host_os = "windows")]
+#[cfg(all(host_os = "windows", not(soong)))]
 const RUSTVERSION: Version = include!(concat!(env!("OUT_DIR"), "\\version.expr"));
 
+#[cfg(all(not(soong), not(trusty)))]
+fn rust_version() -> Version { RUSTVERSION }
+
+#[cfg(any(soong, trusty))]
+fn rust_version() -> Version {
+    let version_str = {
+        #[cfg(soong)]
+        { option_env!("ANDROID_RUST_VERSION") }
+        #[cfg(trusty)]
+        { option_env!("TRUSTY_BUILD_RUST_VERSION") }
+    };
+
+    let v: Vec<&str> = version_str.unwrap().split('.').collect();
+    Version {
+        minor: v[1].parse().unwrap(),
+        patch: v[2].parse().unwrap(),
+        channel: version::Channel::Stable,
+    }
+}
+
 #[proc_macro_attribute]
 pub fn stable(args: TokenStream, input: TokenStream) -> TokenStream {
     expand::cfg("stable", args, input)
@@ -274,7 +294,7 @@ pub fn cfg(input: TokenStream) -> TokenStream {
         let ref mut args = iter::new(input);
         let expr = expr::parse(args)?;
         token::parse_end(args)?;
-        let boolean = expr.eval(RUSTVERSION);
+        let boolean = expr.eval(rust_version());
         let ident = Ident::new(&boolean.to_string(), Span::call_site());
         Ok(TokenStream::from(TokenTree::Ident(ident)))
     })()