dev: avoid warnings from -Wold-style-definition

Author: flavorjones

ext/sqlite3/backup.c

@@ -150,7 +150,7 @@ static VALUE pagecount(VALUE self)
   return INT2NUM(sqlite3_backup_pagecount(ctx->p));
 }
 
-void init_sqlite3_backup()
+void init_sqlite3_backup(void)
 {
 #if 0
   VALUE mSqlite3 = rb_define_module("SQLite3");

ext/sqlite3/database.c

@@ -800,7 +800,7 @@ static VALUE rb_sqlite3_open16(VALUE self, VALUE file)
   return INT2NUM(status);
 }
 
-void init_sqlite3_database()
+void init_sqlite3_database(void)
 {
 #if 0
   VALUE mSqlite3 = rb_define_module("SQLite3");

ext/sqlite3/sqlite3.c

@@ -82,7 +82,7 @@ static VALUE threadsafe_p(VALUE UNUSED(klass))
   return INT2NUM(sqlite3_threadsafe());
 }
 
-void init_sqlite3_constants()
+void init_sqlite3_constants(void)
 {
   VALUE mSqlite3Constants;
   VALUE mSqlite3Open;
@@ -128,7 +128,7 @@ void init_sqlite3_constants()
 }
 
 RUBY_FUNC_EXPORTED
-void Init_sqlite3_native()
+void Init_sqlite3_native(void)
 {
   /*
    * SQLite3 is a wrapper around the popular database

ext/sqlite3/statement.c

@@ -418,7 +418,7 @@ static VALUE database_name(VALUE self, VALUE index)
 
 #endif
 
-void init_sqlite3_statement()
+void init_sqlite3_statement(void)
 {
   cSqlite3Statement = rb_define_class_under(mSqlite3, "Statement", rb_cObject);