Fix mysql2 0.5.5 compatibility issue:

- mysql2 introduces new data type, which led to 'wrong argument type Mysql2::Client (expected Data)'
- mysql_client_wrapper struct updated too

Author: Lucca Kaiser

ext/mysql_blob_streaming/mysql_blob_streaming.c

@@ -15,23 +15,24 @@
 
 typedef struct {
   VALUE encoding;
-  VALUE active_thread;
+  VALUE active_fiber; /* rb_fiber_current() or Qnil */
   long server_version;
   int reconnect_enabled;
-  int connect_timeout;
+  unsigned int connect_timeout;
   int active;
-  int connected;
+  int automatic_close;
   int initialized;
   int refcount;
-  int freed;
+  int closed;
   MYSQL *client;
 } mysql_client_wrapper;
 
+extern const rb_data_type_t rb_mysql_client_type;
 
 static MYSQL * mysql_connection(VALUE rb_mysql2_client)
 {
     mysql_client_wrapper *wrapper;
-    Data_Get_Struct(rb_mysql2_client, mysql_client_wrapper, wrapper);
+    TypedData_Get_Struct(rb_mysql2_client, mysql_client_wrapper, &rb_mysql_client_type, wrapper);
     return wrapper->client;
 }
 

mysql_blob_streaming.gemspec

@@ -13,8 +13,8 @@ Gem::Specification.new do |spec|
   EOF
   spec.license = 'MIT'
 
-  spec.add_dependency 'mysql2', ">= 0.4.4", "< 0.6.0"
-  spec.required_ruby_version = '>=2.0.0'
+  spec.add_dependency "mysql2", ">= 0.5.5"
+  spec.required_ruby_version = "">= 2.0.0"
 
   spec.files = Dir["lib/**/*.rb", "ext/**/*.{c,h,rb}", "README.markdown"]
   spec.extensions = ['ext/mysql_blob_streaming/extconf.rb']