Add spport for pgo

src/bin/cargo/commands/build.rs

@@ -27,6 +27,7 @@ pub fn cli() -> App {
             "Build all targets",
         )
         .arg_release("Build artifacts in release mode, with optimizations")
+        .arg_pgo("Build artifacts in release mode, with profile guide optimizations")
         .arg_profile("Build artifacts with the specified profile")
         .arg_features()
         .arg_target_triple("Build for the target triple")

src/cargo/util/command_prelude.rs

@@ -116,6 +116,10 @@ pub trait AppExt: Sized {
         self._arg(opt("release", release))
     }
 
+    fn arg_pgo(self, pgo: &'static str) -> Self {
+        self._arg(opt("pgo", pgo))
+    }
+
     fn arg_profile(self, profile: &'static str) -> Self {
         self._arg(opt("profile", profile).value_name("PROFILE-NAME"))
     }