[cxx-interop] Fix check to include std::span

Author: susmonteiro

benchmark/utils/CxxTests/CxxStdlibPerformance.h

@@ -5,28 +5,25 @@
 #include <set>
 
 // FIXME swift-ci linux tests do not support std::span
-#if defined(__has_include) && __has_include(<span>)
+#ifndef __linux__
 #include <span>
-#define SPAN_DEFINED 1
-#else
-#define SPAN_DEFINED 0
-#endif
+#endif // __linux__
 
 static const size_t spanSize = 50000;
 
 using VectorOfU32 = std::vector<uint32_t>;
 using SetOfU32 = std::set<uint32_t>;
-#if SPAN_DEFINED
+#ifndef __linux__
 using ArrayOfU32 = uint32_t[spanSize];
 using SpanOfU32 = std::span<uint32_t>;
-#endif
+#endif // __linux__
 
 static inline VectorOfU32 vec;
 static inline SetOfU32 set;
-#if SPAN_DEFINED
+#ifndef __linux__
 static inline ArrayOfU32 array;
 static inline SpanOfU32 span;
-#endif
+#endif // __linux__
 
 inline void initVector(size_t size) {
     if (!vec.empty()) {
@@ -47,7 +44,7 @@ inline void initSet(size_t size) {
     }
 }
 
-#if SPAN_DEFINED
+#ifndef __linux__
 inline void initSpan() {
     if (!span.empty()) {
         return;
@@ -57,7 +54,7 @@ inline void initSpan() {
     }
     span = SpanOfU32(array);
 }
-#endif
+#endif // __linux__
 
 inline VectorOfU32 makeVector32(size_t size) {
     initVector(size);