Include sys/types.h for pid_t

sys/types.h is required for the definition of pid_t.  Fixes a build
failure with musl libc:

In file included from system/extras/memory_replay/AllocParser.cpp:21:
system/extras/memory_replay/AllocParser.h:31:5: error: unknown type name 'pid_t'
    pid_t tid;

Test: m USE_HOST_MUSL=true host-native -k
Change-Id: I6506d23996abb034dc6f806791539f4e6d337bde
diff --git a/memory_replay/AllocParser.h b/memory_replay/AllocParser.h
index e7727b6..e58be48 100644
--- a/memory_replay/AllocParser.h
+++ b/memory_replay/AllocParser.h
@@ -16,6 +16,8 @@
 
 #pragma once
 
+#include <sys/types.h>
+
 #include <string>
 
 enum AllocEnum : uint8_t {