[Bug libstdc++/82033] New: C++11 <thread> library doesn't work on AIX if GCC is built with --disable-bootstrap

["sam.thursfield at codethink dot co.uk" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82033

            Bug ID: 82033
           Summary: C++11 <thread> library doesn't work on AIX if GCC is
                    built with --disable-bootstrap
           Product: gcc
           Version: 7.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sam.thursfield at codethink dot co.uk
  Target Milestone: ---
              Host: powerpc-ibm-aix7.1.0.0
            Target: powerpc-ibm-aix7.1.0.0
             Build: powerpc-ibm-aix7.1.0.0

Here's a simple testcase:

```
#include <string>
#include <iostream>
#include <thread>

using namespace std;

void task1(string msg)
{
    cout << "task1 says: " << msg;
}

int main()
{
    std::thread t1(task1, "Hello");
    t1.join();
}
```

This builds fine using `g++ -std=c++11 -pthread`. *Unless* you built the
compiler with `--disable-bootstrap`. In that case, it fails:

```threadtest.cpp: In function 'int main()':
threadtest.cpp:16:10: error: 'thread' is not a member of 'std'
     std::thread t1(task1, "Hello");
          ^~~~~~
threadtest.cpp:16:10: note: suggested alternative: 'tera'
     std::thread t1(task1, "Hello");
          ^~~~~~
          tera
threadtest.cpp:19:5: error: 't1' was not declared in this scope
     t1.join();
     ^~
threadtest.cpp:19:5: note: suggested alternative: 'tm'
     t1.join();
     ^~
     tm
```