Add unistd.h for size_t typedef to fix sim-eng

Change-Id: Ida4f1742547f39539b601f13182c722aa7cf863e
diff --git a/libs/utils/StreamingZipInflater.cpp b/libs/utils/StreamingZipInflater.cpp
index 2ebec93..c13760a 100644
--- a/libs/utils/StreamingZipInflater.cpp
+++ b/libs/utils/StreamingZipInflater.cpp
@@ -20,6 +20,7 @@
 #include <utils/FileMap.h>
 #include <utils/StreamingZipInflater.h>
 #include <string.h>
+#include <unistd.h>
 #include <assert.h>
 
 static inline size_t min(size_t a, size_t b) { return (a < b) ? a : b; }