--- a/src/dk.h
+++ b/src/dk.h
@@ -17,8 +17,10 @@
 #endif
 
 #ifndef NAN
-	#if __GNUC_PREREQ (3, 3)
-		#define NAN (__builtin_nanf(""))
+	#if defined(__GLIBC__)
+		#if __GNUC_PREREQ (3, 3)
+			#define NAN (__builtin_nanf(""))
+		#endif
 	#else
 		#define NAN (0.0f / 0.0f)
 	#endif