[compiler-rt] [ubsan-minimal] Switch to weak symbols for callbacks to allow overriding in client code (PR #119242)

[Vitaly Buka via llvm-commits]

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@@ -0,0 +1,14 @@
+// RUN: %clang -fsanitize=implicit-integer-sign-change %s -o %t && %run %t 2>&1 | FileCheck %s --check-prefixes=CHECK
+
+#include <stdio.h>
+#include <stdint.h>
+
+void __ubsan_handle_implicit_conversion_minimal() {
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vitalybuka wrote:

```
decorate_msg(MSG_TMPL_END(msg_buf, msg), caller);                          \
    if (report_this_error(caller)) {                                           \
      message(msg_buf);                                                        \
    }                                                                          \
    __sanitizer_report_error_summary(msg_buf);                                 \
```

https://github.com/llvm/llvm-project/pull/119242