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

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: None (michaelrj-google)

<details>
<summary>Changes</summary>

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.


---
Full diff: https://github.com/llvm/llvm-project/pull/81330.diff


1 Files Affected:

- (modified) utils/bazel/llvm-project-overlay/libc/BUILD.bazel (+2) 


``````````diff
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",

``````````

</details>


https://github.com/llvm/llvm-project/pull/81330