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/src/config.mk.in b/src/config.mk.in
index f55bea6..df09cfe 100644
--- a/src/config.mk.in
+++ b/src/config.mk.in
@@ -41,6 +41,7 @@
 LUA_SRC		= @LUA_SRC@
 LUA_OBJ		= @LUA_OBJ@
 LUA_CFLAGS	= @LUA_CFLAGS@
+LUA_CFLAGS_EXTRA	= @LUA_CFLAGS_EXTRA@
 LUA_PRO		= @LUA_PRO@
 
 MZSCHEME_LIBS	= @MZSCHEME_LIBS@
@@ -60,15 +61,18 @@
 PERL_OBJ	= @PERL_OBJ@
 PERL_PRO	= @PERL_PRO@
 PERL_CFLAGS	= @PERL_CFLAGS@
+PERL_CFLAGS_EXTRA	= @PERL_CFLAGS_EXTRA@
 
 PYTHON_SRC	= @PYTHON_SRC@
 PYTHON_OBJ	= @PYTHON_OBJ@
 PYTHON_CFLAGS	= @PYTHON_CFLAGS@
+PYTHON_CFLAGS_EXTRA	= @PYTHON_CFLAGS_EXTRA@
 PYTHON_LIBS	= @PYTHON_LIBS@
 
 PYTHON3_SRC	= @PYTHON3_SRC@
 PYTHON3_OBJ	= @PYTHON3_OBJ@
 PYTHON3_CFLAGS	= @PYTHON3_CFLAGS@
+PYTHON3_CFLAGS_EXTRA	= @PYTHON3_CFLAGS_EXTRA@
 PYTHON3_LIBS	= @PYTHON3_LIBS@
 
 TCL		= @vi_cv_path_tcl@
@@ -76,6 +80,7 @@
 TCL_OBJ		= @TCL_OBJ@
 TCL_PRO		= @TCL_PRO@
 TCL_CFLAGS	= @TCL_CFLAGS@
+TCL_CFLAGS_EXTRA	= @TCL_CFLAGS_EXTRA@
 TCL_LIBS	= @TCL_LIBS@
 
 NETBEANS_SRC	= @NETBEANS_SRC@
@@ -91,6 +96,7 @@
 RUBY_OBJ	= @RUBY_OBJ@
 RUBY_PRO	= @RUBY_PRO@
 RUBY_CFLAGS	= @RUBY_CFLAGS@
+RUBY_CFLAGS_EXTRA	= @RUBY_CFLAGS_EXTRA@
 RUBY_LIBS	= @RUBY_LIBS@
 
 AWK		= @AWK@