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/tools/misc/ethminer/add-global-context.patch

@@ -0,0 +1,25 @@
+diff --git a/libethcore/CMakeLists.txt b/libethcore/CMakeLists.txt
+index 1a53de8..832e926 100644
+--- a/libethcore/CMakeLists.txt
++++ b/libethcore/CMakeLists.txt
+@@ -7,7 +7,7 @@ set(SOURCES
+ include_directories(BEFORE ..)
+ 
+ add_library(ethcore ${SOURCES})
+-target_link_libraries(ethcore PUBLIC devcore ethash::ethash PRIVATE hwmon)
++target_link_libraries(ethcore PUBLIC devcore ethash::ethash ethash-global-context PRIVATE hwmon)
+ 
+ if(ETHASHCL)
+ 	target_link_libraries(ethcore PRIVATE ethash-cl)
+diff --git a/libethcore/EthashAux.h b/libethcore/EthashAux.h
+index d9aadc7..fe5c6cf 100644
+--- a/libethcore/EthashAux.h
++++ b/libethcore/EthashAux.h
+@@ -22,6 +22,7 @@
+ #include <libdevcore/Worker.h>
+ 
+ #include <ethash/ethash.hpp>
++#include <ethash/global_context.hpp>
+ 
+ namespace dev
+ {