Fixed compile error under Windows if winapifamily.h is unavailable (regression of fd842b6).

Author: dmitrykos

src/share/win_utf8_io/win_utf8_io.c

@@ -40,9 +40,12 @@
 #define UTF8_BUFFER_SIZE 32768
 
 /* detect whether it is Windows APP (UWP) or standard Win32 envionment */
-#if defined(WINAPI_FAMILY_PARTITION) &&\
-	WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
-	#define FLAC_WINDOWS_APP 1
+#ifdef WINAPI_FAMILY_PARTITION
+	#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP) && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+		#define FLAC_WINDOWS_APP 1
+	#else
+		#define FLAC_WINDOWS_APP 0
+	#endif
 #else
 	#define FLAC_WINDOWS_APP 0
 #endif