libstdc++ testsuite failures on AIX

[David Edelsohn]

I'm continuing to see about 12 new testsuite failures on AIX.  They
all show similar characteristics complaining about mutex:

FAIL: experimental/net/execution_context/use_service.cc (test for excess errors)
Excess errors:
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:507:
error: 'mutex' in namespace 'std' does not name a type
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:554:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:554:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:554:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:554:
error: 'class std::experimental::net::v1::execution_context' has no member named
 '_M_mutex'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:578:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:578:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:578:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:578:
error: 'class std::experimental::net::v1::execution_context' has no member named
 '_M_mutex'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:600:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:600:
error: 'mutex' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:600:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:600:
error: 'const class std::experimental::net::v1::execution_context' has no member
 named '_M_mutex'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:888:
error: 'thread' does not name a type; did you mean 'fread'?
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:889:
error: 'mutex' does not name a type
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:890:
error: 'condition_variable' does not name a type
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:866:
error: 'mutex' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:866:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:866:
error: '_M_mtx' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:868:
error: '_M_cv' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:873:
error: 'mutex' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:873:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:873:
error: '_M_mtx' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:879:
error: '_M_thread' was not declared in this scope; did you mean '__n_pthreads'?
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:901:
error: 'mutex' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:901:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:901:
error: '_M_mtx' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:902:
error: '_M_cv' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:916:
error: 'mutex' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:916:
error: template argument 1 is invalid
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:916:
error: '_M_mtx' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:919:
error: '_M_thread' was not declared in this scope; did you mean '__n_pthreads'?
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:920:
error: 'thread' is not a member of 'std'
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:922:
error: '_M_cv' was not declared in this scope
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:1489:
 error: 'thread' in namespace 'std' does not name a type
/tmp/GCC/powerpc-ibm-aix7.2.0.0/libstdc++-v3/include/experimental/executor:1453:
 error: 'std::this_thread' has not been declared

UNRESOLVED: experimental/net/execution_context/use_service.cc compilation failed
 to produce executable