[compiler-rt] [compiler-rt][fuchsia] Preallocate a vmar for sanitizer internals (PR #75256)

[Roland McGrath via llvm-commits]

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@@ -129,6 +129,55 @@ uptr GetMaxVirtualAddress() { return GetMaxUserVirtualAddress(); }
 
 bool ErrorIsOOM(error_t err) { return err == ZX_ERR_NO_MEMORY; }
 
+// For any sanitizer internal that needs to map something which can be unmmaped
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frobtech wrote:

typo: "unmapped"

https://github.com/llvm/llvm-project/pull/75256