Use our own release profile to insulate from custom release profiles

src/lib.rs

@@ -347,6 +347,23 @@ version = "0.0.0"
 # empty dummy, just so that things are being built
 path = "lib.rs"
 
+[profile.sysroot_release]
+# While it says "inherits", we override all settings.
+# This is to insulate us from any custom release profile.
+# The only reason we use inherits is because it's required.
+inherits = "release"
+opt-level = 3
+debug = false
+strip = "none"
+split-debuginfo = 'off'
+debug-assertions = false
+overflow-checks = false
+lto = false
+panic = 'unwind'
+incremental = false
+codegen-units = 16
+rpath = false
+
 {crates}
 
 {patches}
@@ -374,7 +391,7 @@ path = "lib.rs"
             Some(v) => v,
             None => rustc_version::version_meta()?,
         };
-
+        
         // The whole point of this crate is to build the standard library in nonstandard
         // configurations, which may trip lints due to untested combinations of cfgs.
         // Cargo applies --cap-lints=allow or --cap-lints=warn when handling -Zbuild-std, which we
@@ -426,7 +443,8 @@ path = "lib.rs"
         // Run cargo.
         let mut cmd = cargo;
         cmd.arg(self.mode.as_str());
-        cmd.arg("--release");
+        cmd.arg("--profile");
+        cmd.arg("sysroot_release");
         cmd.arg("--manifest-path");
         cmd.arg(&manifest_file);
         cmd.arg("--target");