Fix malloc.h is deprecated warning on DragonFly BSD.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85782 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/Process.inc b/lib/System/Unix/Process.inc
index 94e4c1b..911b8c3 100644
--- a/lib/System/Unix/Process.inc
+++ b/lib/System/Unix/Process.inc
@@ -18,7 +18,9 @@
 #ifdef HAVE_SYS_RESOURCE_H
 #include <sys/resource.h>
 #endif
-#ifdef HAVE_MALLOC_H
+// DragonFly BSD has deprecated <malloc.h> for <stdlib.h> instead,
+//  Unix.h includes this for us already.
+#if defined(HAVE_MALLOC_H) && !defined(__DragonFly__)
 #include <malloc.h>
 #endif
 #ifdef HAVE_MALLOC_MALLOC_H