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/servers/foundationdb/patches/clang-libcxx.patch

@@ -0,0 +1,52 @@
+commit 7ed4745a092a203f92fc37ab5894e92117db0c94
+Author: Austin Seipp <aseipp@pobox.com>
+Date:   Sat May 4 15:23:35 2019 -0500
+
+    flow: fix a build failure with Clang/libcxx on Linux
+    
+    11bd7d7da introduced a hack on Linux to work around a missing symbol in
+    libstdc++'s _pic library on Ubuntu. Unfortunately, this causes the build
+    to fail when using Clang, as it doesn't believe this symbol is part of
+    its headers in c++11 mode.
+    
+    Unfortunately there's no good way to distinguish libcxx from libstdc++
+    with the preprocessor, so we merely gate it by only checking for clang,
+    iff we are on Linux.
+    
+    With this change, Clang 8.x can build FoundationDB on Linux using libcxx
+    as the standard C++ library.
+    
+    Signed-off-by: Austin Seipp <aseipp@pobox.com>
+
+diff --git a/flow/Platform.cpp b/flow/Platform.cpp
+index 3d3f1ac0..9f21dfd4 100644
+--- a/flow/Platform.cpp
++++ b/flow/Platform.cpp
+@@ -2841,13 +2841,26 @@ void setupSlowTaskProfiler() {
+ #endif
+ }
+ 
+-#ifdef __linux__
++#if defined(__linux__) && !defined(__clang__)
+ // There's no good place to put this, so it's here.
+ // Ubuntu's packaging of libstdc++_pic offers different symbols than libstdc++.  Go figure.
+ // Notably, it's missing a definition of std::istream::ignore(long), which causes compilation errors
+ // in the bindings.  Thus, we provide weak versions of their definitions, so that if the
+ // linked-against libstdc++ is missing their definitions, we'll be able to use the provided
+ // ignore(long, int) version.
++//
++// Note that this hack is DISABLED when we use Clang. It is only needed when we statically link
++// to the _pic libraries, but only official FDB Linux binaries are built this way using GCC. If we
++// don't use the _pic libraries, then this hack is entirely unneeded -- likely the case when using
++// Clang on Linux.
++//
++// Doing this allows us to use LLVM's libc++ with Clang on Linux -- otherwise, providing
++// a weak symbol definition for an internal (non-public) class member fails (due to that member
++// being non-existant on libc++.) See upstream GitHub issue #1533 for more information.
++//
++// TODO FIXME: Obliterate this when the official build environment is upgraded beyond Ubuntu 14.04.
++// (This problem should be fixed in later LTS releases.)
++
+ #include <istream>
+ namespace std {
+ typedef basic_istream<char, std::char_traits<char>> char_basic_istream;