patch 8.2.0297: compiler warnings for the Ruby interface

Problem:    Compiler warnings for the Ruby interface.
Solution:   Undefine a few macros, fix initialization. (Ozaki Kiichi,
            closes #5677)
diff --git a/src/if_ruby.c b/src/if_ruby.c
index f4e1e12..a4a59f6 100644
--- a/src/if_ruby.c
+++ b/src/if_ruby.c
@@ -209,6 +209,14 @@
 /*
  * Wrapper defines
  */
+// Ruby 2.7 actually expands the following symbols as macro.
+# if RUBY_VERSION >= 27
+#  undef rb_define_global_function
+#  undef rb_define_method
+#  undef rb_define_module_function
+#  undef rb_define_singleton_method
+# endif
+
 # define rb_assoc_new			dll_rb_assoc_new
 # define rb_cObject			(*dll_rb_cObject)
 # define rb_class_new_instance		dll_rb_class_new_instance
@@ -1228,7 +1236,7 @@
     "vim_buffer",
     {0, 0, buffer_dsize,
 # if RUBY_VERSION >= 27
-	0, 0
+	0, {0}
 # else
 	{0, 0}
 # endif
@@ -1508,7 +1516,7 @@
     "vim_window",
     {0, 0, window_dsize,
 # if RUBY_VERSION >= 27
-	0, 0
+	0, {0}
 # else
 	{0, 0}
 # endif
diff --git a/src/version.c b/src/version.c
index 5eb0d05..aa9ff36 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    297,
+/**/
     296,
 /**/
     295,