unix: update Dockerfile to Linux 5.6, and Go 1.13.9

We cannot update to Go 1.14 yet, since cgo code generation for certain
types is broken due to golang/go#37621.

Change-Id: I7b60d23ff4e79a7bb7fa4f0e0625893e4eff81f1
Reviewed-on: https://go-review.googlesource.com/c/sys/+/226577
Run-TryBot: Tobias Klauser <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Matt Layher <[email protected]>

Author: tklauser

unix/linux/Dockerfile

@@ -12,15 +12,16 @@ RUN apt-get update && apt-get install -y  --no-install-recommends \
 # Get the git sources. If not cached, this takes O(5 minutes).
 WORKDIR /git
 RUN git config --global advice.detachedHead false
-# Linux Kernel: Released 27 Jan 2020
-RUN git clone --branch v5.5 --depth 1 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
+# Linux Kernel: Released 29 Mar 2020
+RUN git clone --branch v5.6 --depth 1 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
 # GNU C library: Released 01 Feb 2020 (we should try to get a secure way to clone this)
 RUN git clone --branch release/2.31/master --depth 1 git://sourceware.org/git/glibc.git
 
 # Get Go
-ENV GOLANG_VERSION 1.13.7
+# TODO: update to Go 1.14 once there is a minor release with https://golang.org/issue/37622 fixed.
+ENV GOLANG_VERSION 1.13.9
 ENV GOLANG_DOWNLOAD_URL https://golang.org/dl/go$GOLANG_VERSION.linux-amd64.tar.gz
-ENV GOLANG_DOWNLOAD_SHA256 b3dd4bd781a0271b33168e627f7f43886b4c5d1c794a4015abf34e99c6526ca3
+ENV GOLANG_DOWNLOAD_SHA256 f4ad8180dd0aaf7d7cda7e2b0a2bf27e84131320896d376549a7d849ecf237d7
 
 RUN curl -fsSL "$GOLANG_DOWNLOAD_URL" -o golang.tar.gz \
     && echo "$GOLANG_DOWNLOAD_SHA256  golang.tar.gz" | sha256sum -c - \

unix/mkerrors.sh

@@ -486,6 +486,7 @@ ccflags="$@"
 		$2 ~ /^LINUX_REBOOT_MAGIC[12]$/ ||
 		$2 ~ /^MODULE_INIT_/ ||
 		$2 !~ "NLA_TYPE_MASK" &&
+		$2 !~ /^RTC_VL_(ACCURACY|BACKUP|DATA)/ &&
 		$2 ~ /^(NETLINK|NLM|NLMSG|NLA|IFA|IFAN|RT|RTC|RTCF|RTN|RTPROT|RTNH|ARPHRD|ETH_P|NETNSA)_/ ||
 		$2 ~ /^SIOC/ ||
 		$2 ~ /^TIOC/ ||