Decommision src_common prior to reintroducing it for files common between eth and plugins

src/mem.h

@@ -0,0 +1,15 @@
+#ifndef MEM_H_
+#define MEM_H_
+
+#ifdef HAVE_DYN_MEM_ALLOC
+
+#include <stdlib.h>
+
+void mem_init(void);
+void mem_reset(void);
+void *mem_alloc(size_t size);
+void mem_dealloc(size_t size);
+
+#endif  // HAVE_DYN_MEM_ALLOC
+
+#endif  // MEM_H_