Upgrade rust/crates/proc-macro-hack to 0.5.19
Test: make
Change-Id: I3ca9b7f663f7fa6b81473e30e37940593c0c4af9
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..6ab4098
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,31 @@
+use std::env;
+use std::process::Command;
+use std::str;
+
+// The rustc-cfg strings below are *not* public API. Please let us know by
+// opening a GitHub issue if your build environment requires some way to enable
+// these cfgs other than by executing our build script.
+fn main() {
+ let minor = match rustc_minor_version() {
+ Some(minor) => minor,
+ None => return,
+ };
+
+ // Function-like procedural macros in expressions, patterns, and statements
+ // stabilized in Rust 1.45:
+ // https://blog.rust-lang.org/2020/07/16/Rust-1.45.0.html#stabilizing-function-like-procedural-macros-in-expressions-patterns-and-statements
+ if minor < 45 {
+ println!("cargo:rustc-cfg=need_proc_macro_hack");
+ }
+}
+
+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()
+}