Fix macOS build.

Bug: http://b/177702122
Test: treehugger
Change-Id: I64ad7f506fb241c5f949c7bbac55a26161bd510e
diff --git a/libcutils/memory.cpp b/libcutils/memory.cpp
index a899d80..5a410c2 100644
--- a/libcutils/memory.cpp
+++ b/libcutils/memory.cpp
@@ -18,7 +18,9 @@
 
 #include <log/log.h>
 
+#if !defined(__APPLE__)
 #include <malloc.h>
+#endif
 
 void process_disable_memory_mitigations() {
     bool success = false;