Remove OS(QNX) support.

Source/wtf/MathExtras.h

Index: Source/wtf/MathExtras.h
diff --git a/Source/wtf/MathExtras.h b/Source/wtf/MathExtras.h
index 47441128aa90db6849118cb0df19cbfb8089672d..e4b63e1c1c1aff8bdbe2a07f909d118f11fa5c0a 100644
--- a/Source/wtf/MathExtras.h
+++ b/Source/wtf/MathExtras.h
@@ -43,13 +43,6 @@
 #include <machine/ieee.h>
 #endif
 
-#if OS(QNX)
-// FIXME: Look into a way to have cmath import its functions into both the standard and global
-// namespace. For now, we include math.h since the QNX cmath header only imports its functions
-// into the standard namespace.
-#include <math.h>
-#endif
-
 #ifndef M_PI
 const double piDouble = 3.14159265358979323846;
 const float piFloat = 3.14159265358979323846f;
@@ -141,11 +134,6 @@ inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
 
 #endif
 
-#if COMPILER(GCC) && OS(QNX)
-// The stdlib on QNX doesn't contain long abs(long). See PR #104666.
-inline long long abs(long num) { return labs(num); }
-#endif
-
 #if OS(ANDROID) || COMPILER(MSVC)
 // ANDROID and MSVC's math.h does not currently supply log2 or log2f.
 inline double log2(double num)