Delete dependency on config.h

[kadircet]

Summary

Since llvm/Config/config.h is not available on standalone builds,
use __USE_POSIX instead of HAVE_PTHREAD_H and get rid of the include.

[lebedev.ri]

How does this play with LLVM_ENABLE_THREADS cmake option?

[sammccall]

clangd/Threading.cpp

7 ↗

(On Diff #171929)

nit: just ifdef?

[sammccall]

clangd/Threading.cpp

104 ↗

(On Diff #171929)

the posix seems redundant here too

[kadircet]

• Address comments.

[sammccall]

In D53935#1282303, @lebedev.ri wrote:

How does this play with LLVM_ENABLE_THREADS cmake option?

Clangd doesn't support/respect that, and I don't think anyone's building in that configuration.
If this causes actual problems e.g. with bots, we should sort out a cmake solution so such bots don't build clangd.

clang-tools-extra/trunk/clangd/Threading.cpp

 #include "Threading.h"
 #include "Trace.h"
 #include "llvm/ADT/ScopeExit.h"
-#include "llvm/Config/config.h"
 #include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/Threading.h"
 #include <thread>
-#ifdef HAVE_PTHREAD_H
+#ifdef __USE_POSIX
 #include <pthread.h>
 #endif
 
 using namespace llvm;
 namespace clang {
 namespace clangd {
 
 void Notification::notify() {
void wait(std::unique_lock<std::mutex> &Lock, std::condition_variable &CV,
   if (D == Deadline::zero())
     return;
   if (D == Deadline::infinity())
     return CV.wait(Lock);
   CV.wait_until(Lock, D.time());
 }
 
 void setThreadPriority(std::thread &T, ThreadPriority Priority) {
-#if defined(HAVE_PTHREAD_H) && defined(__linux__)
+#ifdef __linux__
   sched_param priority;
   priority.sched_priority = 0;
   pthread_setschedparam(
       T.native_handle(),
       Priority == ThreadPriority::Low ? SCHED_IDLE : SCHED_OTHER, &priority);
 #endif
 }
 
 } // namespace clangd
 } // namespace clang