fixing bitfield misuse

http_parser.h

@@ -70,8 +70,25 @@ struct http_parser {
   enum http_parser_type type;
 
   size_t chunk_size;
-  unsigned eating:1;
-  unsigned error:1;
+
+  /**
+    XXX
+    do this so no other code has to change, but make the field only 1 byte wide
+    instead of 2 (on x86/x86_64).
+
+    doing this not only shrinks the sizeof this struct by a byte but it ALSO
+    makes wrapping this in FFI way easier.
+   */
+  union {
+    struct {
+      unsigned eating:1;
+      unsigned error:1;
+    };
+    struct {
+      unsigned char _flags;
+    };
+  };
+
   size_t body_read;
 
   const char *header_field_mark;