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/libraries/libmpc/default.nix

@@ -0,0 +1,41 @@
+{ lib, stdenv, fetchurl
+, gmp, mpfr
+}:
+
+# Note: this package is used for bootstrapping fetchurl, and thus
+# cannot use fetchpatch! All mutable patches (generated by GitHub or
+# cgit) that are needed here should be included directly in Nixpkgs as
+# files.
+
+stdenv.mkDerivation rec {
+  pname = "libmpc";
+  version = "1.2.1"; # to avoid clash with the MPD client
+
+  src = fetchurl {
+    url = "mirror://gnu/mpc/mpc-${version}.tar.gz";
+    sha256 = "0n846hqfqvmsmim7qdlms0qr86f1hck19p12nq3g3z2x74n3sl0p";
+  };
+
+  strictDeps = true;
+  enableParallelBuilding = true;
+
+  buildInputs = [ gmp mpfr ];
+
+  doCheck = true; # not cross;
+
+  meta = {
+    description = "Library for multiprecision complex arithmetic with exact rounding";
+
+    longDescription =
+      '' GNU MPC is a C library for the arithmetic of complex numbers with
+         arbitrarily high precision and correct rounding of the result.  It is
+         built upon and follows the same principles as GNU MPFR.
+      '';
+
+    homepage = "http://mpc.multiprecision.org/";
+    license = lib.licenses.lgpl2Plus;
+
+    platforms = lib.platforms.all;
+    maintainers = [ ];
+  };
+}