patch 8.2.3922: cannot build with dynamic Ruby 3.1

Problem:    Cannot build with dynamic Ruby 3.1.
Solution:   Add "_EXTRA" variables for CI.  Add missing functions. (Ozaki
            Kiichi, closes #9420)
diff --git a/ci/config.mk.sed b/ci/config.mk.sed
index cd2cd9c..51e7ec9 100644
--- a/ci/config.mk.sed
+++ b/ci/config.mk.sed
@@ -1,2 +1,3 @@
 /^CFLAGS[[:blank:]]*=/s/$/ -Wall -Wextra -Wshadow -Werror/
-/^PERL_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unused-function/
+/^PERL_CFLAGS_EXTRA[[:blank:]]*=/s/$/ -Wno-error=unused-function/
+/^RUBY_CFLAGS_EXTRA[[:blank:]]*=/s/$/ -Wno-error=unused-parameter/