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/setup-hooks/enable-coverage-instrumentation.sh

@@ -0,0 +1,20 @@
+postPhases+=" cleanupBuildDir"
+
+# Force GCC to build with coverage instrumentation.  Also disable
+# optimisation, since it may confuse things.
+export NIX_CFLAGS_COMPILE="${NIX_CFLAGS_COMPILE:-} -O0 --coverage"
+
+# Get rid of everything that isn't a gcno file or a C source file.
+# Also strip the `.tmp_' prefix from gcno files.  (The Linux kernel
+# creates these.)
+cleanupBuildDir() {
+    if ! [ -e $out/.build ]; then return; fi
+
+    find $out/.build/ -type f -a ! \
+        \( -name "*.c" -o -name "*.cc" -o -name "*.cpp" -o -name "*.h" -o -name "*.hh" -o -name "*.y" -o -name "*.l" -o -name "*.gcno" \) \
+        | xargs rm -f --
+
+    for i in $(find $out/.build/ -name ".tmp_*.gcno"); do
+        mv "$i" "$(echo $i | sed s/.tmp_//)"
+    done
+}