darwin: pthread/spawn.h gives unknown type name 'qos_class_t'

[matthewbauer]

Issue description

When updating to Bazel 0.26, an #include <pthread/spawn.h> is added to blaze_util_darwin.cc. This results in darwin: pthread/spawn.h gives unknown type name. A workaround is used by including dispatch/dispatch.h instead.

This is the log:

In file included from src/main/cpp/blaze_util_darwin.cc:24:
/nix/store/mffyf74zc4h2wic5lwx0kyx7gvwif0c5-Libsystem-osx-10.12.6/include/pthread/spawn.h:65:34: error: unknown type name 'qos_class_t'; did you mean 'au_class_t'?
                                 qos_class_t __qos_class);
                                 ^
/nix/store/mffyf74zc4h2wic5lwx0kyx7gvwif0c5-Libsystem-osx-10.12.6/include/bsm/audit.h:176:19: note: 'au_class_t' declared here
typedef u_int32_t       au_class_t;
                        ^
In file included from src/main/cpp/blaze_util_darwin.cc:24:
/nix/store/mffyf74zc4h2wic5lwx0kyx7gvwif0c5-Libsystem-osx-10.12.6/include/pthread/spawn.h:88:34: error: unknown type name 'qos_class_t'; did you mean 'au_class_t'?
                                 qos_class_t * __restrict __qos_class);
                                 ^
/nix/store/mffyf74zc4h2wic5lwx0kyx7gvwif0c5-Libsystem-osx-10.12.6/include/bsm/audit.h:176:19: note: 'au_class_t' declared here
typedef u_int32_t       au_class_t;
                        ^
2 errors generated.

Tried to reproduce this with:

#include <sys/types.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/un.h>

#include <libproc.h>
#include <pthread/spawn.h>
#include <signal.h>
#include <spawn.h>
#include <stdlib.h>
#include <unistd.h>

#include <cerrno>
#include <cstdio>
#include <cstring>

int ConfigureDaemonProcess(posix_spawnattr_t *attrp) {
  return posix_spawnattr_set_qos_class_np(attrp, QOS_CLASS_DEFAULT);
}

but did not get the same error! Need to investigate it further.

[lilyball]

This sounds very strange; I just tested myself and clang -E pthread/spawn.h with the appropriate system directories set up does declare qos_class_t prior to any uses of it. All I can figure out is that (prior to including the headers) defining _ANSI_SOURCE or _POSIX_C_SOURCE (or defining _XOPEN_SOURCE with a value of 500L or greater) could cause this behavior, except I see no reason why any of these would be defined.

[stale]

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