[clang] [compiler-rt] [ASan] Document define to disable container overflow checks at compile time. (PR #163468)

[Louis Dionne via cfe-commits]

================
@@ -242,6 +255,43 @@ AddressSanitizer also supports
 works similar to ``__attribute__((no_sanitize("address")))``, but it also
 prevents instrumentation performed by other sanitizers.
 
+Disabling container overflow checks
+-----------------------------------
+
+Runtime suppression
+^^^^^^^^^^^^^^^^^^^
+
+Container overflow checks can be disabled at runtime using
+``ASAN_OPTIONS=detect_container_overflow=0``
----------------
ldionne wrote:

```suggestion
Container overflow checks can be disabled at runtime using the
``ASAN_OPTIONS=detect_container_overflow=0`` environment variable.
```

Assuming that's an environment variable?

https://github.com/llvm/llvm-project/pull/163468