uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

pkgs/build-support/rust/sysroot/cargo.py

@@ -0,0 +1,47 @@
+import os
+import toml
+
+rust_src = os.environ['RUSTC_SRC']
+orig_cargo = os.environ['ORIG_CARGO'] if 'ORIG_CARGO' in os.environ else None
+
+base = {
+  'package': {
+    'name': 'nixpkgs-sysroot-stub-crate',
+    'version': '0.0.0',
+    'authors': ['The Rust Project Developers'],
+    'edition': '2018',
+  },
+  'dependencies': {
+    'compiler_builtins': {
+      'version': '0.1.0',
+      'features': ['rustc-dep-of-std', 'mem'],
+    },
+    'core': {
+      'path': os.path.join(rust_src, 'core'),
+    },
+    'alloc': {
+      'path': os.path.join(rust_src, 'alloc'),
+    },
+  },
+  'patch': {
+    'crates-io': {
+      'rustc-std-workspace-core': {
+        'path': os.path.join(rust_src, 'rustc-std-workspace-core'),
+      },
+      'rustc-std-workspace-alloc': {
+        'path': os.path.join(rust_src, 'rustc-std-workspace-alloc'),
+      },
+    },
+  },
+}
+
+if orig_cargo is not None:
+  with open(orig_cargo, 'r') as f:
+    src = toml.loads(f.read())
+    if 'profile' in src:
+      base['profile'] = src['profile']
+
+out = toml.dumps(base)
+
+with open('Cargo.toml', 'x') as f:
+  f.write(out)