uboot: Apply patches outside container

When running inside a rootless Podman container on a SELinux-enabled
host, the `patch` command fails because it cannot copy SELinux labels
from the original file to the patched file.  This only happens patching
files that are located in a bind mount.

build-uboot.sh

@@ -5,14 +5,8 @@ set -e
 
 . ./config
 
+./patch-uboot.sh
 cd u-boot
-if [ ! -f .patched ]; then
-    for x in ../patches/uboot/*.patch; do
-        printf 'Applying patch %s ...\n' "${x##*/}"
-        patch -p1 < "${x}"
-    done
-    : > .patched
-fi
 cat configs/rpi_4_defconfig ../u-boot.config > configs/yellow_defconfig
 make yellow_defconfig
 CROSS_COMPILE=${target}- make

patch-uboot.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# vim: set sw=4 ts=4 sts=4 et :
+
+if [ -f u-boot/.patched ]; then
+    exit 0
+fi
+
+rc=0
+cd u-boot || exit
+for x in ../patches/uboot/*.patch; do
+    [ -f "${x}" ] || continue
+    printf 'Applying patch %s ...\n' "${x##*/}"
+    patch -p1 < "${x}" || rc=$?
+done
+if [ $rc -eq 0 ]; then
+    : > .patched
+fi

podman-build.sh

@@ -20,6 +20,8 @@ cid=$(podman run \
     python -c 'from signal import *;signal(SIGTERM, lambda x, y: None);pause()'
 )
 
+./patch-uboot.sh
+
 podman exec -it ${cid} ./build-all.sh "${target}"
 
 podman stop ${cid}