diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index 73da4e4e2..7243f010f 100644
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -1933,7 +1933,7 @@ static void malloc_update_mallinfo(void)
   int i;
   mbinptr b;
   mchunkptr p;
-#if DEBUG
+#ifdef DEBUG
   mchunkptr q;
 #endif
 
@@ -1945,7 +1945,7 @@ static void malloc_update_mallinfo(void)
     b = bin_at(i);
     for (p = last(b); p != b; p = p->bk)
     {
-#if DEBUG
+#ifdef DEBUG
       check_free_chunk(p);
       for (q = next_chunk(p);
 	   q < top && inuse(q) && (long)(chunksize(q)) >= (long)MINSIZE;
diff --git a/include/malloc.h b/include/malloc.h
index 7decc71b7..047e965a9 100644
--- a/include/malloc.h
+++ b/include/malloc.h
@@ -472,7 +472,7 @@ do {                                                                          \
 #define HAVE_MMAP 1
 #endif
 ***/
-#undef	HAVE_MMAP	/* Not available for U-Boot */
+#define	HAVE_MMAP 0	/* Not available for U-Boot */
 
 /*
   Define HAVE_MREMAP to make realloc() use mremap() to re-allocate