qemu_multiarch_testing: small improvements

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/qemu_multiarch_testing/extract_uuencoded_binary.sh b/qemu_multiarch_testing/extract_uuencoded_binary.sh
new file mode 100755
index 0000000..6739993
--- /dev/null
+++ b/qemu_multiarch_testing/extract_uuencoded_binary.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+# Extract uuencoded and bzipped busybox binaries
+# from system-image-*.log files
+
+for logfile in system-image-*.log; do
+	grep -q '^begin 744 busybox.bz2' "$logfile" \
+	|| { echo "No busybox.bz2 in $logfile"; continue; }
+
+	arch=${logfile%.log}
+	arch=${arch#system-image-}
+
+	test -e "busybox-$arch" \
+	&& { echo "busybox-$arch exists, not overwriting"; continue; }
+
+	uudecode -o - "$logfile" | bunzip2 >"busybox-$arch" \
+	&& chmod 755 "busybox-$arch"
+done
diff --git a/qemu_multiarch_testing/hdc.dir/build b/qemu_multiarch_testing/hdc.dir/build
index a998186..c9e1a37 100755
--- a/qemu_multiarch_testing/hdc.dir/build
+++ b/qemu_multiarch_testing/hdc.dir/build
@@ -29,12 +29,13 @@
 		sed 's/^.*CONFIG_EXTRA_CFLAGS.*$/CONFIG_EXTRA_CFLAGS="-mips32"/' -i .config
 	}
 	# These won't build because of toolchain/libc breakage:
-	sed 's/^.*CONFIG_FEATURE_SYNC_FANCY.*$/# CONFIG_FEATURE_SYNC_FANCY is not set/' -i .config # no syncfs()
+	sed 's/^.*CONFIG_FEATURE_SYNC_FANCY.*$/# CONFIG_FEATURE_SYNC_FANCY is not set/' -i .config # no syncfs() on armv4l, sparc
 	sed 's/^.*CONFIG_FEATURE_WTMP.*$/# CONFIG_FEATURE_WTMP is not set/' -i .config
 	sed 's/^.*CONFIG_FEATURE_UTMP.*$/# CONFIG_FEATURE_UTMP is not set/' -i .config
 	sed 's/^.*CONFIG_FEATURE_INETD_RPC.*$/# CONFIG_FEATURE_INETD_RPC is not set/' -i .config
 
 	make #V=1 || sh
+	test -f busybox || exit 1
 	size busybox
 	./busybox || echo "Exit code: $?"
 	if uuencode TEST </dev/null >/dev/null && bzip2 </dev/null >/dev/null; then