Remove OS(QNX) support.

Source/wtf/Atomics.h

Index: Source/wtf/Atomics.h
diff --git a/Source/wtf/Atomics.h b/Source/wtf/Atomics.h
index 9b4a4681d4013fd7ca9fdd3a8162040421bec577..2f69dc213387918194b69a96ebd8e654f3e0c5f4 100644
--- a/Source/wtf/Atomics.h
+++ b/Source/wtf/Atomics.h
@@ -65,8 +65,6 @@
 
 #if OS(WINDOWS)
 #include <windows.h>
-#elif OS(QNX)
-#include <atomic.h>
 #elif OS(ANDROID)
 #include <sys/atomics.h>
 #endif
@@ -90,13 +88,6 @@ inline int64_t atomicIncrement(int64_t volatile* addend) { return InterlockedInc
 inline int64_t atomicDecrement(int64_t volatile* addend) { return InterlockedDecrement64(reinterpret_cast<long long volatile*>(addend)); }
 #endif
 
-#elif OS(QNX)
-#define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1
-
-// Note, atomic_{add, sub}_value() return the previous value of addend's content.
-inline int atomicIncrement(int volatile* addend) { return static_cast<int>(atomic_add_value(reinterpret_cast<unsigned volatile*>(addend), 1)) + 1; }
-inline int atomicDecrement(int volatile* addend) { return static_cast<int>(atomic_sub_value(reinterpret_cast<unsigned volatile*>(addend), 1)) - 1; }
-
 #elif OS(ANDROID)
 #define WTF_USE_LOCKFREE_THREADSAFEREFCOUNTED 1