diff --git a/ci/config.mk.clang.sed b/ci/config.mk.clang.sed
index 2e27c7c..da6044d 100644
--- a/ci/config.mk.clang.sed
+++ b/ci/config.mk.clang.sed
@@ -1,2 +1,2 @@
 /^CFLAGS[[:blank:]]*=/s/$/ -Wno-error=missing-field-initializers/
-/^RUBY_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes -fms-extensions/
+/^RUBY_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unknown-attributes -Wno-error=ignored-attributes/
diff --git a/src/auto/configure b/src/auto/configure
index f2486e9..ebeed2c 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -7651,6 +7651,9 @@
 	  RUBY_CFLAGS="-DDYNAMIC_RUBY_DLL=\\\"$libruby_soname\\\" $RUBY_CFLAGS"
 	  RUBY_LIBS=
 	fi
+	if test "X$CLANG_VERSION" != "X" -a "$rubyversion" -ge 30; then
+	  RUBY_CFLAGS="$RUBY_CFLAGS -fdeclspec"
+	fi
       else
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not found; disabling Ruby" >&5
 $as_echo "not found; disabling Ruby" >&6; }
diff --git a/src/configure.ac b/src/configure.ac
index c024f65..d13e378 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -2001,6 +2001,9 @@
 	  RUBY_CFLAGS="-DDYNAMIC_RUBY_DLL=\\\"$libruby_soname\\\" $RUBY_CFLAGS"
 	  RUBY_LIBS=
 	fi
+	if test "X$CLANG_VERSION" != "X" -a "$rubyversion" -ge 30; then
+	  RUBY_CFLAGS="$RUBY_CFLAGS -fdeclspec"
+	fi
       else
 	AC_MSG_RESULT(not found; disabling Ruby)
       fi
diff --git a/src/version.c b/src/version.c
index 39d2f26..e9327f1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2241,
+/**/
     2240,
 /**/
     2239,