Remove unnecessary compiler pragma.

With dlmalloc 2.8.6 the compiler pragmas to suppress warnings are not
necessary.
Remove unnecessary dlmalloc dl prefix #define.

Depends upon: https://android-review.googlesource.com/42351

Change-Id: Idc45cee9342efec0aab63d5172b3308a0fca3c4f
diff --git a/vm/alloc/DlMalloc.cpp b/vm/alloc/DlMalloc.cpp
index 8638ab5..1571801 100644
--- a/vm/alloc/DlMalloc.cpp
+++ b/vm/alloc/DlMalloc.cpp
@@ -36,11 +36,7 @@
  * dlmalloc for our use for mspaces (regular dlmalloc is still declared
  * in bionic).
  */
-#pragma GCC diagnostic ignored "-Wempty-body"
-#pragma GCC diagnostic ignored "-Wstrict-aliasing"
 #include "../../../bionic/libc/upstream-dlmalloc/malloc.c"
-#pragma GCC diagnostic warning "-Wstrict-aliasing"
-#pragma GCC diagnostic warning "-Wempty-body"
 
 
 static void heap_error(const char* msg, const char* function, void* p) {
diff --git a/vm/alloc/DlMalloc.h b/vm/alloc/DlMalloc.h
index e28c7e5..f076656 100644
--- a/vm/alloc/DlMalloc.h
+++ b/vm/alloc/DlMalloc.h
@@ -24,7 +24,6 @@
 #define MSPACES 1
 #define NO_MALLINFO 1
 #define ONLY_MSPACES 1
-#define USE_DL_PREFIX 1
 #define MALLOC_INSPECT_ALL 1
 
 /* Include the proper definitions. */