diff --git a/indra/llcommon/stdtypes.h b/indra/llcommon/stdtypes.h
index da8512169c689826cdd8ded90f97b2b34cea82f9..0b43d7ad4b4c272da5026cefa8c4773509863dfa 100644
--- a/indra/llcommon/stdtypes.h
+++ b/indra/llcommon/stdtypes.h
@@ -41,7 +41,7 @@ typedef unsigned int			U32;
 
 // to express an index that might go negative
 // (ssize_t is provided by SOME compilers, don't collide)
-typedef typename std::make_signed<size_t>::type llssize;
+typedef typename std::make_signed<std::size_t>::type llssize;
 
 #if LL_WINDOWS
 // https://docs.microsoft.com/en-us/cpp/build/reference/zc-wchar-t-wchar-t-is-native-type