Add config option to use dlmalloc instead of mheap

Configure w/ --enable-dlmalloc, see .../build-data/platforms/vpp.mk

src/vppinfra/dlmalloc.[ch] are slightly modified versions of the
well-known Doug Lea malloc. Main advantage: dlmalloc mspaces have no
inherent size limit.

Change-Id: I19b3f43f3c65bcfb82c1a265a97922d01912446e
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vppinfra/mheap.c b/src/vppinfra/mheap.c
index 0c72c88..5b71873 100644
--- a/src/vppinfra/mheap.c
+++ b/src/vppinfra/mheap.c
@@ -975,6 +975,29 @@
 }
 
 void *
+mheap_alloc_with_lock (void *memory, uword size, int locked)
+{
+  uword flags = 0;
+  void *rv;
+
+  if (memory != 0)
+    flags |= MHEAP_FLAG_DISABLE_VM;
+
+#ifdef CLIB_HAVE_VEC128
+  flags |= MHEAP_FLAG_SMALL_OBJECT_CACHE;
+#endif
+
+  rv = mheap_alloc_with_flags (memory, size, flags);
+
+  if (rv && locked)
+    {
+      mheap_t *h = mheap_header (rv);
+      h->flags |= MHEAP_FLAG_THREAD_SAFE;
+    }
+  return rv;
+}
+
+void *
 _mheap_free (void *v)
 {
   mheap_t *h = mheap_header (v);