Upgrade rust/crates/anyhow to 1.0.37

Test: make
Change-Id: Ibc6ae300f243375e5d9c9f6874f87e32c817c943

1 files changed, 25 insertions, 5 deletions

diff --git a/build.rs b/build.rs
index d20b072..a7dc8f2 100644
--- a/build.rs
+++ b/build.rs
@@ -2,6 +2,7 @@ use std::env;
 use std::fs;
 use std::path::Path;
 use std::process::{Command, ExitStatus, Stdio};
+use std::str;
 
 // This code exercises the surface area that we expect of the std Backtrace
 // type. If the current toolchain is able to compile it, we go ahead and use
@@ -35,12 +36,20 @@ const PROBE: &str = r#"
 "#;
 
 fn main() {
-    if !cfg!(feature = "std") {
-        return;
+    if cfg!(feature = "std") {
+        match compile_probe() {
+            Some(status) if status.success() => println!("cargo:rustc-cfg=backtrace"),
+            _ => {}
+        }
     }
-    match compile_probe() {
-        Some(status) if status.success() => println!("cargo:rustc-cfg=backtrace"),
-        _ => {}
+
+    let rustc = match rustc_minor_version() {
+        Some(rustc) => rustc,
+        None => return,
+    };
+
+    if rustc < 38 {
+        println!("cargo:rustc-cfg=anyhow_no_macro_reexport");
     }
 }
 
@@ -61,3 +70,14 @@ fn compile_probe() -> Option<ExitStatus> {
         .status()
         .ok()
 }
+
+fn rustc_minor_version() -> Option<u32> {
+    let rustc = env::var_os("RUSTC")?;
+    let output = Command::new(rustc).arg("--version").output().ok()?;
+    let version = str::from_utf8(&output.stdout).ok()?;
+    let mut pieces = version.split('.');
+    if pieces.next() != Some("rustc 1") {
+        return None;
+    }
+    pieces.next()?.parse().ok()
+}