diff --git a/http/bit.lua b/http/bit.lua
index 0f6f0b69..3a95d1ed 100644
--- a/http/bit.lua
+++ b/http/bit.lua
@@ -7,16 +7,18 @@ The bit operations are only done
 This means we can ignore the differences between bit libraries.
 ]]
 
--- Lua 5.3 has built-in bit operators, wrap them in a function.
-if _VERSION == "Lua 5.3" then
-	-- Use debug.getinfo to get correct file+line numbers for loaded snippet
-	local info = debug.getinfo(1, "Sl")
-	return assert(load(("\n"):rep(info.currentline+1)..[[return {
-		band = function(a, b) return a & b end;
-		bor = function(a, b) return a | b end;
-		bxor = function(a, b) return a ~ b end;
-	}]], info.source))()
-end
+-- Lua 5.1 uses loadstring for load with a string, Lua 5.2+ just
+-- uses load.
+local load = loadstring or load
+
+-- Lua 5.3+ has built-in bit operators, wrap them in a function.
+local info = debug.getinfo(1, "Sl")
+local has_bitwise, bitwise = pcall(load(("\n"):rep(info.currentline+1)..[[return {
+	band = function(a, b) return a & b end;
+	bor = function(a, b) return a | b end;
+	bxor = function(a, b) return a ~ b end;
+}]], info.source))
+if has_bitwise then return bitwise end
 
 -- The "bit" library that comes with luajit
 -- also available for lua 5.1 as "luabitop": http://bitop.luajit.org/