Add missing header.

malloc/free are being used if SWIFTSHADER_TRANSLATOR_DISABLE_POOL_ALLOC
is defined.

Change-Id: I213c9d614b38fecdc673be5058d5f6f2bc579ca6
Reviewed-on: https://swiftshader-review.googlesource.com/19968
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/OpenGL/compiler/PoolAlloc.cpp b/src/OpenGL/compiler/PoolAlloc.cpp
index 1235023..94f9cc9 100644
--- a/src/OpenGL/compiler/PoolAlloc.cpp
+++ b/src/OpenGL/compiler/PoolAlloc.cpp
@@ -18,6 +18,7 @@
 #include <stdint.h>
 #endif
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "InitializeGlobals.h"
 #include "osinclude.h"