Make tests work on public repo as well

PUBLISHED_FROM=78acb18d597b6f47f31da13087fa6685f21ce445

src/common/platforms/esp8266/esp_umm_malloc.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2014 Cesanta Software Limited
+ * All rights reserved
+ */
+
+#if ESP_UMM_ENABLE
+
+/*
+ * This is a no-op dummy function that is merely needed because we have to
+ * reference any function from the file `esp_umm_malloc.c`, so that linker
+ * won't garbage-collect the whole compilation unit.
+ */
+void esp_umm_init(void);
+
+/*
+ * Callback that gets called by umm_malloc in case of Out-of-memory error.
+ *
+ * `size` is the size requested by user, and `block_cnt` is a number of heap
+ * blocks that umm_malloc failed to allocate
+ */
+void esp_umm_oom_cb(size_t size, size_t blocks_cnt);
+
+#endif /* CS_COMMON_PLATFORMS_ESP8266_ESP_UMM_MALLOC_H_ */