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/development/compilers/swift/patches/0005-clang-toolchain-dir.patch

@@ -0,0 +1,13 @@
+Use the Nix include dirs and gcc runtime dir, when no sysroot is configured.
+
+--- a/lib/Driver/ToolChains/Linux.cpp
++++ b/lib/Driver/ToolChains/Linux.cpp
+@@ -574,7 +574,7 @@
+
+   // Check for configure-time C include directories.
+   StringRef CIncludeDirs(C_INCLUDE_DIRS);
+-  if (CIncludeDirs != "") {
++  if (CIncludeDirs != "" && (SysRoot.empty() || SysRoot == "/")) {
+     SmallVector<StringRef, 5> dirs;
+     CIncludeDirs.split(dirs, ":");
+     for (StringRef dir : dirs) {