RFR: 8282475: SafeFetch should not rely on existence of Thread::current [v7]

[Andrew Haley]

On Sat, 12 Mar 2022 07:45:57 GMT, Florian Weimer <fweimer at openjdk.org> wrote:

> into the assembler sources and use
> 
> ```c++
>         extern char address_of_label[] __attribute__ ((visibility ("hidden")));

ITYM

extern "C" char address_of_label[] __attribute__ ((visibility ("hidden")));

-------------

PR: https://git.openjdk.java.net/jdk/pull/7727