fix for older gcc

include/o3tl/typed_flags_set.hxx: In instantiation of 'o3tl::is_typed_flags<ImplFontAttrs, -0x00000000000000001>':
include/unotools/fontcfg.hxx:88:94:   instantiated from here
include/o3tl/typed_flags_set.hxx:66:5: error: static assertion failed: "is_typed_flags expects only non-negative bit values"

Change-Id: Ica7873bef3fd664370a96d8066d63c473ff6798f

include/unotools/fontcfg.hxx

@@ -85,7 +85,7 @@ enum class ImplFontAttrs : sal_uLong
 };
 namespace o3tl
 {
-    template<> struct typed_flags<ImplFontAttrs> : is_typed_flags<ImplFontAttrs, 0xffffffff> {};
+    template<> struct typed_flags<ImplFontAttrs> : is_typed_flags<ImplFontAttrs, 0xffffffffUL> {};
 }