Fixed compilation in IAR Embedded Workbench (issue #515)

src/ArduinoJson/Polyfills/attributes.hpp

@@ -7,11 +7,14 @@
 
 #pragma once
 
-#ifdef _MSC_VER
+#ifdef _MSC_VER  // Visual Studio
+
 #define FORCE_INLINE __forceinline
 #define NO_INLINE __declspec(noinline)
 #define DEPRECATED(msg) __declspec(deprecated(msg))
-#else
+
+#elif defined(__GNUC__)  // GCC or Clang
+
 #define FORCE_INLINE __attribute__((always_inline))
 #define NO_INLINE __attribute__((noinline))
 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
@@ -19,4 +22,11 @@
 #else
 #define DEPRECATED(msg) __attribute__((deprecated))
 #endif
+
+#else  // Other compilers
+
+#define FORCE_INLINE
+#define NO_INLINE
+#define DEPRECATED(msg)
+
 #endif