Index: build/premake/extern_libs5.lua
===================================================================
--- build/premake/extern_libs5.lua
+++ build/premake/extern_libs5.lua
@@ -218,7 +218,9 @@
 	},
 	cxxtest = {
 		compile_settings = function()
-			sysincludedirs { libraries_source_dir .. "cxxtest-4.4" }
+			if not _OPTIONS["with-system-cxxtest"] then
+				sysincludedirs { libraries_source_dir .. "cxxtest-4.4" }
+			end
 		end,
 	},
 	enet = {
Index: build/premake/premake5.lua
===================================================================
--- build/premake/premake5.lua
+++ build/premake/premake5.lua
@@ -7,6 +7,7 @@
 newoption { trigger = "minimal-flags", description = "Only set compiler/linker flags that are really needed. Has no effect on Windows builds" }
 newoption { trigger = "outpath", description = "Location for generated project files" }
 newoption { trigger = "with-system-mozjs52", description = "Search standard paths for libmozjs52, instead of using bundled copy" }
+newoption { trigger = "with-system-cxxtest", description = "Search standard paths for cxxtest, instead of using bundled copy" }
 newoption { trigger = "with-system-nvtt", description = "Search standard paths for nvidia-texture-tools library, instead of using bundled copy" }
 newoption { trigger = "without-audio", description = "Disable use of OpenAL/Ogg/Vorbis APIs" }
 newoption { trigger = "without-lobby", description = "Disable the use of gloox and the multiplayer lobby" }
@@ -1327,7 +1328,11 @@
 	if os.istarget("windows") then
 		cxxtest.setpath(rootdir.."/build/bin/cxxtestgen.exe")
 	else
-		cxxtest.setpath(rootdir.."/libraries/source/cxxtest-4.4/bin/cxxtestgen")
+		if not _OPTIONS["with-system-cxxtest"] then
+			cxxtest.setpath(rootdir.."/libraries/source/cxxtest-4.4/bin/cxxtestgen")
+		else
+			cxxtest.setpath("/usr/bin/cxxtestgen")
+		end
 	end
 
 	local runner = "ErrorPrinter"