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/mpfr/default.nix

@@ -0,0 +1,55 @@
+{ lib, stdenv, fetchurl, gmp }:
+
+# 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 {
+  version = "4.1.0";
+  pname = "mpfr";
+
+  src = fetchurl {
+    urls = [
+      #"https://www.mpfr.org/${name}/${name}.tar.xz"
+      "mirror://gnu/mpfr/${pname}-${version}.tar.xz"
+    ];
+    sha256 = "0zwaanakrqjf84lfr5hfsdr7hncwv9wj0mchlr7cmxigfgqs760c";
+  };
+
+  outputs = [ "out" "dev" "doc" "info" ];
+
+  strictDeps = true;
+  # mpfr.h requires gmp.h
+  propagatedBuildInputs = [ gmp ];
+
+  configureFlags =
+    lib.optional stdenv.hostPlatform.isSunOS "--disable-thread-safe" ++
+    lib.optional stdenv.hostPlatform.is64bit "--with-pic";
+
+  doCheck = true; # not cross;
+
+  enableParallelBuilding = true;
+
+  meta = {
+    homepage = "https://www.mpfr.org/";
+    description = "Library for multiple-precision floating-point arithmetic";
+
+    longDescription = ''
+      The GNU MPFR library is a C library for multiple-precision
+      floating-point computations with correct rounding.  MPFR is
+      based on the GMP multiple-precision library.
+
+      The main goal of MPFR is to provide a library for
+      multiple-precision floating-point computation which is both
+      efficient and has a well-defined semantics.  It copies the good
+      ideas from the ANSI/IEEE-754 standard for double-precision
+      floating-point arithmetic (53-bit mantissa).
+    '';
+
+    license = lib.licenses.lgpl2Plus;
+
+    maintainers = [ ];
+    platforms = lib.platforms.all;
+  };
+}