Changed TIM_DIV265 for deprecation (esp8266#4326)

Author: devyte

cores/esp8266/Arduino.h

@@ -85,9 +85,13 @@ extern "C" {
 #define EXTERNAL 0
 
 //timer dividers
-#define TIM_DIV1 	0 //80MHz (80 ticks/us - 104857.588 us max)
-#define TIM_DIV16	1 //5MHz (5 ticks/us - 1677721.4 us max)
-#define TIM_DIV265	3 //312.5Khz (1 tick = 3.2us - 26843542.4 us max)
+enum TIM_DIV_ENUM {
+  TIM_DIV1 = 0,   //80MHz (80 ticks/us - 104857.588 us max)
+  TIM_DIV16 = 1,  //5MHz (5 ticks/us - 1677721.4 us max)
+  TIM_DIV256 = 3 //312.5Khz (1 tick = 3.2us - 26843542.4 us max)
+};
+
+
 //timer int_types
 #define TIM_EDGE	0
 #define TIM_LEVEL	1
@@ -236,7 +240,17 @@ void optimistic_yield(uint32_t interval_us);
 } // extern "C"
 #endif
 
+
+//for compatibility, below 4 lines to be removed in release 3.0.0
 #ifdef __cplusplus
+extern "C"
+#endif
+const int TIM_DIV265 __attribute__((deprecated, weak)) = TIM_DIV256;
+
+
+
+#ifdef __cplusplus
+
 #include <algorithm>
 #include "pgmspace.h"