Fix issues that will be present in C++11

- char16_t is a distinct type, so stay consistent
  with it throughout the code base.
- char16_t is defined as minimum size of 16 bits.
  Since we mmap and cast data structures onto raw memory,
  we need a precise definition (uint16_t), so we cast between
  that (and static_assert that they are the same size).

Change-Id: I869c32637543bbcfb39d2643e7d9df10d33acd3c
diff --git a/tools/aapt/StringPool.h b/tools/aapt/StringPool.h
index 1b3abfd..a9c7bec 100644
--- a/tools/aapt/StringPool.h
+++ b/tools/aapt/StringPool.h
@@ -26,7 +26,10 @@
 
 #define PRINT_STRING_METRICS 0
 
-void strcpy16_htod(uint16_t* dst, const uint16_t* src);
+#if __cplusplus >= 201103L
+void strcpy16_htod(char16_t* dst, const char16_t* src);
+#endif
+void strcpy16_htod(uint16_t* dst, const char16_t* src);
 
 void printStringPool(const ResStringPool* pool);