[llvm] [libc][bazel] mark read and write as weak (PR #81330)

[via llvm-commits]

https://github.com/michaelrj-google created https://github.com/llvm/llvm-project/pull/81330

Downstream there's a user that intercepts these functions and overlays
them. This causes symbol conflicts if neither function is marked weak.
In future the intent is to move to this to being a downstream configuration
option.


>From 0eeb08d4c611101e27e49f14c6393f55379332a5 Mon Sep 17 00:00:00 2001
From: Michael Jones <michaelrj at google.com>
Date: Fri, 9 Feb 2024 14:48:02 -0800
Subject: [PATCH] [libc][bazel] mark read and write as weak

Downstream there's a user that intercepts these functions and overlays
them. This causes symbol conflicts if neither function is marked weak.
In future the intent is to move to this to being a downstream configuration
option.
---
 utils/bazel/llvm-project-overlay/libc/BUILD.bazel | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
index fd6d1dc047f428..4aef47c6e44b1e 100644
--- a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
@@ -2803,6 +2803,7 @@ libc_function(
     name = "read",
     srcs = ["src/unistd/linux/read.cpp"],
     hdrs = ["src/unistd/read.h"],
+    weak = True,
     deps = [
         ":__support_common",
         ":__support_macros_sanitizer",
@@ -2928,6 +2929,7 @@ libc_function(
     name = "write",
     srcs = ["src/unistd/linux/write.cpp"],
     hdrs = ["src/unistd/write.h"],
+    weak = True,
     deps = [
         ":__support_common",
         ":__support_osutil_syscall",