Merge pull request #2778 from apple/runtime-remove-unused-includes

runtime: remove unused includes

Author: gribozavr

stdlib/public/runtime/Errors.cpp

@@ -19,7 +19,6 @@
 #include <string.h>
 #include <stdint.h>
 #include <unistd.h>
-#include <pthread.h>
 #include <stdarg.h>
 #include "swift/Runtime/Debug.h"
 #include "swift/Runtime/Mutex.h"

stdlib/public/runtime/MetadataLookup.cpp

@@ -34,8 +34,6 @@
 #include <link.h>
 #endif
 
-#include <dlfcn.h>
-
 using namespace swift;
 using namespace Demangle;
 

stdlib/public/runtime/Reflection.mm

@@ -24,7 +24,6 @@
 #include <cstring>
 #include <new>
 #include <string>
-#include <dlfcn.h>
 
 #if SWIFT_OBJC_INTEROP
 #include "swift/Runtime/ObjCBridge.h"