configure.ac: rename extra_warning as extra_warnflags

Adjusted to warnflags variable.  This variable will have flags for
warnings, but not a warning itself.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65806 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.ac

@@ -476,10 +476,10 @@ rb_cv_warnflags="$warnflags"
 AS_CASE(["$GCC:${warnflags+set}:${extra_warnflags:+set}:"],
 [yes::*|yes:*:set:], [# GCC && (!warnflags || extra_warnflags)
     AS_IF([test $gcc_major -ge 4], [
-	extra_warning="$extra_warning -Werror=extra-tokens"
+	extra_warnflags="$extra_warnflags -Werror=extra-tokens"
     ])
     AS_IF([test $gcc_major -ge 5 -a $gcc_major -le 6], [
-	extra_warning="$extra_warning -Wno-maybe-uninitialized"
+	extra_warnflags="$extra_warnflags -Wno-maybe-uninitialized"
     ])
     # ICC doesn't support -Werror=
     AS_IF([test $icc_version -gt 0], [
@@ -514,7 +514,7 @@ AS_CASE(["$GCC:${warnflags+set}:${extra_warnflags:+set}:"],
 		 -Wsuggest-attribute=noreturn \
 		 -Wunused-variable \
 		 -diag-disable=175,188,2259 \
-		 $extra_warning \
+		 $extra_warnflags \
 		 ; do
 	AS_IF([test "$particular_werror_flags" != yes], [
 	    wflag=`echo x$wflag | sed 's/^x-Werror=/-W/;s/^x//'`