Use umm_malloc for heap management

cores/esp8266/heap.c

@@ -0,0 +1,43 @@
+/* heap.c - overrides of SDK heap handling functions
+ * Copyright (c) 2016 Ivan Grokhotkov. All rights reserved.
+ * This file is distributed under MIT license.
+ */
+
+#include <stdlib.h>
+#include "umm_malloc/umm_malloc.h"
+#include <c_types.h>
+
+void* ICACHE_RAM_ATTR pvPortMalloc(size_t size, const char* file, int line)
+{
+    return malloc(size);
+}
+
+void ICACHE_RAM_ATTR vPortFree(void *ptr, const char* file, int line)
+{
+    free(ptr);
+}
+
+void* ICACHE_RAM_ATTR pvPortCalloc(size_t count, size_t size, const char* file, int line)
+{
+    return calloc(count, size);
+}
+
+void* ICACHE_RAM_ATTR pvPortRealloc(void *ptr, size_t size, const char* file, int line)
+{
+    return realloc(ptr, size);
+}
+
+void* ICACHE_RAM_ATTR pvPortZalloc(size_t size, const char* file, int line)
+{
+    return calloc(1, size);
+}
+
+size_t ICACHE_RAM_ATTR xPortGetFreeHeapSize(void)
+{
+    return umm_free_heap_size();
+}
+
+void system_show_malloc(void)
+{
+    umm_info(NULL, 1);
+}