[core] Split lt_api.c into separate units

cores/common/base/api/lt_mem.c

@@ -0,0 +1,26 @@
+/* Copyright (c) Kuba Szczodrzyński 2022-04-29. */
+
+#include "lt_mem.h"
+
+#if LT_HAS_FREERTOS
+#include <FreeRTOS.h>
+#include <task.h>
+#endif
+
+#if LT_HAS_FREERTOS
+__attribute__((weak)) uint32_t lt_heap_get_size() {
+	return configTOTAL_HEAP_SIZE;
+}
+
+__attribute__((weak)) uint32_t lt_heap_get_free() {
+	return xPortGetFreeHeapSize();
+}
+
+__attribute__((weak)) uint32_t lt_heap_get_min_free() {
+	return xPortGetMinimumEverFreeHeapSize();
+}
+#endif
+
+__attribute__((weak)) uint32_t lt_heap_get_max_alloc() {
+	return 0;
+}