diff --git a/scripts/src/3rdparty.lua b/scripts/src/3rdparty.lua
index 27383c3a8ed..04155ef55a8 100644
--- a/scripts/src/3rdparty.lua
+++ b/scripts/src/3rdparty.lua
@@ -1432,6 +1432,14 @@ end
 		end
 	end
 
+	if _OPTIONS["targetos"]=="macosx" and _OPTIONS["gcc"]~=nil then
+		if string.find(_OPTIONS["gcc"], "clang") and (version < 80000) then
+			defines {
+				"TARGET_OS_OSX=1",
+			}
+		end
+	end
+
 	files {
 		MAME_DIR .. "3rdparty/bgfx/src/bgfx.cpp",
 		MAME_DIR .. "3rdparty/bgfx/src/debug_renderdoc.cpp",