--- a/libtomcrypt/src/headers/tomcrypt_custom.h	Sun May 21 10:48:18 2017 +0800
+++ b/libtomcrypt/src/headers/tomcrypt_custom.h	Sun May 21 10:54:11 2017 +0800
@@ -4,6 +4,17 @@
 /* compile options depend on Dropbear options.h */
 #include "options.h"
 
+void * m_malloc(size_t size);
+/* m_calloc is limited in size, enough for libtomcrypt */
+void * m_calloc(size_t nmemb, size_t size);
+void * m_realloc(void* ptr, size_t size);
+void m_free_direct(void* ptr);
+
+#define XMALLOC m_malloc
+#define XFREE m_free_direct
+#define XREALLOC m_realloc
+#define XCALLOC m_calloc
+
 /* macros for various libc functions you can change for embedded targets */
 #ifndef XMALLOC
    #ifdef malloc