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/pkg-config-wrapper/setup-hook.sh

@@ -0,0 +1,29 @@
+# pkg-config Wrapper hygiene
+#
+# See comments in cc-wrapper's setup hook. This works exactly the same way.
+
+# Skip setup hook if we're neither a build-time dep, nor, temporarily, doing a
+# native compile.
+#
+# TODO(@Ericson2314): No native exception
+[[ -z ${strictDeps-} ]] || (( "$hostOffset" < 0 )) || return 0
+
+pkgConfigWrapper_addPkgConfigPath () {
+    # See ../setup-hooks/role.bash
+    local role_post
+    getHostRoleEnvHook
+
+    addToSearchPath "PKG_CONFIG_PATH${role_post}" "$1/lib/pkgconfig"
+    addToSearchPath "PKG_CONFIG_PATH${role_post}" "$1/share/pkgconfig"
+}
+
+# See ../setup-hooks/role.bash
+getTargetRole
+getTargetRoleWrapper
+
+addEnvHooks "$targetOffset" pkgConfigWrapper_addPkgConfigPath
+
+export PKG_CONFIG${role_post}=@targetPrefix@@baseBinName@
+
+# No local scope in sourced file
+unset -v role_post