asus-me176c: upgrade mainline kernel to 5.4.20, enable Anbox options (!942)

The patch set for asus-me176c is really small at this point, and there
is no need to make a new tag for each minor kernel update. Usually the
previous patch set will still apply correctly.

Refactor the APKBUILD to build the kernel similar to linux-lts in Alpine,
and use the original kernel tarball together with a small patch file on top.

Also enable Android-related options in the kernel so we can test
Anbox on asus-me176c.

device/linux-asus-me176c/APKBUILD

@@ -3,7 +3,9 @@
 
 _flavor="asus-me176c"
 pkgname="linux-$_flavor"
-pkgver=5.4.17
+pkgver=5.4.20
+_kernver=${pkgver%.*}
+_me176cver=5.4.17
 pkgrel=0
 pkgdesc="Mainline kernel fork for ASUS MeMO Pad 7 (ME176C(X))"
 arch="x86_64"
@@ -14,19 +16,21 @@ options="!strip !check !tracedeps"
 depends_dev="perl gmp-dev elfutils-dev bash flex bison mpc1-dev mpfr-dev"
 makedepends="$depends_dev sed installkernel bc linux-headers openssl-dev diffutils xz"
 
-# Compiler: latest GCC from Alpine
-HOSTCC="${CC:-gcc}"
-HOSTCC="${HOSTCC#${CROSS_COMPILE}}"
-
 # Source
 source="
-	$pkgname-$pkgver.tar.gz::$url/archive/$pkgver.tar.gz
+	https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/linux-$_kernver.tar.xz
+	linux-$pkgver.patch.xz::https://cdn.kernel.org/pub/linux/kernel/v${pkgver%%.*}.x/patch-$pkgver.xz
+	https://github.com/me176c-dev/linux-me176c/releases/download/$_me176cver/linux-me176c-$_me176cver.patch.xz
 	config-$_flavor.$arch
 "
-builddir="$srcdir/linux-me176c-$pkgver"
+builddir="$srcdir/linux-$_kernver"
 
 prepare() {
 	default_prepare
+
+	# FIXME: Remove when https://gitlab.alpinelinux.org/alpine/abuild/merge_requests/23 is merged
+	unxz -c "$srcdir/"*.patch.xz | patch -p1
+
 	cp "$srcdir/config-$_flavor.$arch" .config
 }
 
@@ -48,5 +52,7 @@ package() {
 		"$pkgdir"/usr/share/kernel/$_flavor/kernel.release
 }
 
-sha512sums="f666b41fd2b9e6775367542f0ca8f94f21232cedce71d077490e3e49dbb04566d391cdb108a1ee1fb844f34e2a7007bc2f9c384fc8ac6e361309623479ab1887  linux-asus-me176c-5.4.17.tar.gz
+sha512sums="9f60f77e8ab972b9438ac648bed17551c8491d6585a5e85f694b2eaa4c623fbc61eb18419b2656b6795eac5deec0edaa04547fc6723fbda52256bd7f3486898f  linux-5.4.tar.xz
-4e45a11e13ec1978f7954bb5977ee7defd55cf0a64a8876468d72474bd1ef2fe232f61185e770c7198bb66871028d2f4fcf511381a6270aa974008f6ed824579  config-asus-me176c.x86_64"
+65fbcdbd41e35c17601ff15bbe33933be2ab7a694aa181a0b802cc11c1c653c9b688dbb382076cbad05983a0c07467955c035ae25f5175f7ce5bc24339303d77  linux-5.4.20.patch.xz
+aa462bfcbba87469a617e2ffd4058cd41137b74f836aae47ac89bc70de2836b8f3ddce94f597e61bb287eb009bb71f4e831c487b0073011673d5db4a8d8ae080  linux-me176c-5.4.17.patch.xz
+66b9350c59cc6853d8cf9efe98065df900e017d0e1ebf294b9de7a8bd888a6dee9589a8cfc0ac8ebdb757a1d710be2d7ec5b82169b525c3fa43601a6f57161a8  config-asus-me176c.x86_64"

device/linux-asus-me176c/config-asus-me176c.x86_64

@@ -1,6 +1,6 @@
 #
 # Automatically generated file; DO NOT EDIT.
-# Linux/x86_64 5.4.17 Kernel Configuration
+# Linux/x86_64 5.4.20 Kernel Configuration
 #
 
 #
@@ -2674,7 +2674,7 @@ CONFIG_INPUT_MOUSEDEV_PSAUX=y
 CONFIG_INPUT_MOUSEDEV_SCREEN_X=1024
 CONFIG_INPUT_MOUSEDEV_SCREEN_Y=768
 CONFIG_INPUT_JOYDEV=m
-CONFIG_INPUT_EVDEV=m
+CONFIG_INPUT_EVDEV=y
 # CONFIG_INPUT_EVBUG is not set
 
 #
@@ -5415,7 +5415,103 @@ CONFIG_VIRTIO_MENU=y
 # end of Microsoft Hyper-V guest support
 
 # CONFIG_GREYBUS is not set
-# CONFIG_STAGING is not set
+CONFIG_STAGING=y
+# CONFIG_PRISM2_USB is not set
+# CONFIG_COMEDI is not set
+# CONFIG_RTL8192U is not set
+# CONFIG_RTLLIB is not set
+# CONFIG_RTL8723BS is not set
+# CONFIG_R8712U is not set
+# CONFIG_R8188EU is not set
+# CONFIG_RTS5208 is not set
+# CONFIG_VT6655 is not set
+# CONFIG_VT6656 is not set
+
+#
+# IIO staging drivers
+#
+
+#
+# Accelerometers
+#
+# end of Accelerometers
+
+#
+# Analog to digital converters
+#
+# end of Analog to digital converters
+
+#
+# Analog digital bi-direction converters
+#
+# CONFIG_ADT7316 is not set
+# end of Analog digital bi-direction converters
+
+#
+# Capacitance to digital converters
+#
+# CONFIG_AD7150 is not set
+# CONFIG_AD7746 is not set
+# end of Capacitance to digital converters
+
+#
+# Direct Digital Synthesis
+#
+# end of Direct Digital Synthesis
+
+#
+# Network Analyzer, Impedance Converters
+#
+# CONFIG_AD5933 is not set
+# end of Network Analyzer, Impedance Converters
+
+#
+# Active energy metering IC
+#
+# CONFIG_ADE7854 is not set
+# end of Active energy metering IC
+
+#
+# Resolver to digital converters
+#
+# end of Resolver to digital converters
+# end of IIO staging drivers
+
+# CONFIG_FB_SM750 is not set
+
+#
+# Speakup console speech
+#
+# CONFIG_SPEAKUP is not set
+# end of Speakup console speech
+
+# CONFIG_STAGING_MEDIA is not set
+
+#
+# Android
+#
+CONFIG_ASHMEM=y
+# CONFIG_ANDROID_VSOC is not set
+# CONFIG_ION is not set
+# end of Android
+
+# CONFIG_LTE_GDM724X is not set
+# CONFIG_GS_FPGABOOT is not set
+# CONFIG_UNISYSSPAR is not set
+# CONFIG_WILC1000_SDIO is not set
+# CONFIG_MOST is not set
+# CONFIG_KS7010 is not set
+
+#
+# Gasket devices
+#
+# CONFIG_STAGING_GASKET_FRAMEWORK is not set
+# end of Gasket devices
+
+# CONFIG_FIELDBUS_DEV is not set
+# CONFIG_USB_WUSB_CBAF is not set
+# CONFIG_UWB is not set
+# CONFIG_EXFAT_FS is not set
 CONFIG_X86_PLATFORM_DEVICES=y
 # CONFIG_ACER_WIRELESS is not set
 # CONFIG_ACERHDF is not set
@@ -5971,7 +6067,11 @@ CONFIG_RAS=y
 #
 # Android
 #
-# CONFIG_ANDROID is not set
+CONFIG_ANDROID=y
+CONFIG_ANDROID_BINDER_IPC=y
+# CONFIG_ANDROID_BINDERFS is not set
+CONFIG_ANDROID_BINDER_DEVICES="binder,hwbinder,vndbinder"
+# CONFIG_ANDROID_BINDER_IPC_SELFTEST is not set
 # end of Android
 
 # CONFIG_LIBNVDIMM is not set
@@ -6167,8 +6267,8 @@ CONFIG_SQUASHFS=m
 # CONFIG_SQUASHFS_FILE_CACHE is not set
 CONFIG_SQUASHFS_FILE_DIRECT=y
 # CONFIG_SQUASHFS_DECOMP_SINGLE is not set
-CONFIG_SQUASHFS_DECOMP_MULTI=y
+# CONFIG_SQUASHFS_DECOMP_MULTI is not set
-# CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU is not set
+CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU=y
 CONFIG_SQUASHFS_XATTR=y
 CONFIG_SQUASHFS_ZLIB=y
 CONFIG_SQUASHFS_LZ4=y