Insert -Zbuild-std when building rust packages

Otherwise we are linking a copy of the standard library built with some
particular version of emscripten selected by the rust compiler that does not
match the version we are using. This can lead to an ABI mismatch.

See rust-lang/rust#131467

Author: hoodmane

pyodide_build/pywasmcross.py

@@ -525,6 +525,9 @@ def handle_command_generate_args(  # noqa: C901
     elif cmd == "strip":
         line[0] = "emstrip"
         return line
+    elif cmd == "cargo":
+        line.insert(1, "-Zbuild-std")
+        return line
     else:
         return line