unix: switch to Ubuntu 24.10 in Dockerfile

ubuntu 24.04 introduced support for qemu-loongarch64, and ubuntu 24.10
introduced support for the cross-compiler gcc-loongarch64-linux-gnu, so
we can temporarily switch to ubuntu 24.10 to discard the extra links
introduced by loong64 and switch to it when the next ubuntu LTS version
is released.

Change-Id: I96de123df0cf50d6ba0331eeb02fc1e8c48ce304
Reviewed-on: https://go-review.googlesource.com/c/sys/+/618075
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>

Author: abner-chenc

unix/linux/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:20.04
+FROM ubuntu:24.10
 
 # Disable interactive prompts on package installation
 ENV DEBIAN_FRONTEND noninteractive
@@ -48,24 +48,10 @@ RUN apt-get update && apt-get install -y \
         gcc-powerpc-linux-gnu       gcc-powerpc64-linux-gnu   \
         gcc-powerpc64le-linux-gnu   gcc-riscv64-linux-gnu     \
         gcc-s390x-linux-gnu         gcc-sparc64-linux-gnu     \
+        gcc-loongarch64-linux-gnu \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
-# Only for loong64, getting tools of qemu-user and gcc-cross-compiler
-ENV LOONG64_BASE_URL https://github.com/loongson/build-tools/releases/download/2023.08.08
-ENV LOONG64_GCC  CLFS-loongarch64-8.1-x86_64-cross-tools-gcc-glibc.tar.xz
-ENV LOONG64_QEMU qemu-loongarch64
-ENV LOONG64_GCC_DOWNLOAD_URL  $LOONG64_BASE_URL/$LOONG64_GCC
-ENV LOONG64_QEMU_DOWNLOAD_URL $LOONG64_BASE_URL/$LOONG64_QEMU
-
-RUN apt-get update && apt-get install xz-utils -y && mkdir /loong64 && cd /loong64 \
-    && curl -fsSL "$LOONG64_QEMU_DOWNLOAD_URL" -o /usr/bin/"$LOONG64_QEMU" \
-    && chmod +x /usr/bin/"$LOONG64_QEMU" \
-    && curl -fsSL "$LOONG64_GCC_DOWNLOAD_URL" -o "$LOONG64_GCC" \
-    && tar xf "$LOONG64_GCC" -C /usr/local/ \
-    && ln -s /usr/local/cross-tools/bin/loongarch64-unknown-linux-gnu-gcc /usr/bin/loongarch64-linux-gnu-gcc \
-    && rm -rf /loong64
-
 # Let the scripts know they are in the docker environment
 ENV GOLANG_SYS_BUILD docker
 WORKDIR /build/unix

unix/linux/types.go

@@ -20,6 +20,21 @@ package unix
 #define _FILE_OFFSET_BITS 64
 #define _GNU_SOURCE
 
+// Ref: include/linux/time32.h
+//
+// On Linux, in order to solve the overflow problem of time_t type variables on
+// 32-bit arm, mips, and powerpc in 2038, the definition of time_t is switched
+// from a 32-bit field to a 64-bit field. For backward compatibility, we force
+// the use of 32-bit fields.
+#if defined(__ARM_EABI__) || \
+	(defined(__mips__) && (_MIPS_SIM == _ABIO32)) || \
+	(defined(__powerpc__) && (!defined(__powerpc64__)))
+# ifdef  _TIME_BITS
+#  undef _TIME_BITS
+# endif
+# define _TIME_BITS 32
+#endif
+
 #include <dirent.h>
 #include <fcntl.h>
 #include <poll.h>

unix/mkerrors.sh

@@ -158,6 +158,16 @@ includes_Linux='
 #endif
 #define _GNU_SOURCE
 
+// See the description in unix/linux/types.go
+#if defined(__ARM_EABI__) || \
+	(defined(__mips__) && (_MIPS_SIM == _ABIO32)) || \
+	(defined(__powerpc__) && (!defined(__powerpc64__)))
+# ifdef   _TIME_BITS
+#  undef  _TIME_BITS
+# endif
+# define  _TIME_BITS 32
+#endif
+
 // <sys/ioctl.h> is broken on powerpc64, as it fails to include definitions of
 // these structures. We just include them copied from <bits/termios.h>.
 #if defined(__powerpc__)