patch u-boot to add ubifs support

not that we're using it yet

overlay.nix

@@ -199,4 +199,17 @@ extraPkgs // {
   };
 
   strace = prev.strace.override { libunwind = null; };
+
+  ubootQemuArm = final.buildUBoot {
+    defconfig = "qemu_arm_defconfig";
+    extraMeta.platforms = ["armv7l-linux"];
+    filesToInstall = ["u-boot.bin"];
+    # enable looking for boot files on ubifs. this is unused at
+    # present, but added in the expectation of a future test
+    extraPatches = [ ./pkgs/u-boot/0001-add-ubifs-to-boot-targets.patch ];
+    extraConfig = ''
+      CONFIG_CMD_UBI=y
+      CONFIG_CMD_UBIFS=y
+    '';
+  };
 }

pkgs/u-boot/0001-add-ubifs-to-boot-targets.patch

@@ -0,0 +1,12 @@
+diff --git a/include/configs/qemu-arm.h b/include/configs/qemu-arm.h
+index 535762ecb2..a947bae2e8 100644
+--- a/include/configs/qemu-arm.h
++++ b/include/configs/qemu-arm.h
+@@ -72,6 +72,7 @@
+ 	BOOT_TARGET_SCSI(func) \
+ 	BOOT_TARGET_VIRTIO(func) \
+ 	BOOT_TARGET_NVME(func) \
++	func(UBIFS, ubifs, 0, UBI, boot) \
+ 	BOOT_TARGET_DHCP(func)
+ 
+ #include <config_distro_bootcmd.h>