Fix global warnings if strictness is enabled

process_bridges.lua

@@ -3,10 +3,10 @@ function set_insecure_environment(env)
     env = env or _G
     os_execute = env.os.execute
     local socket
-    local original_require = _G.require
-    _G.require = env.require
+    local original_require = rawget(_G, "require")
+    rawset(_G, "require", env.require)
     pcall(function() socket = env.require"socket" end)
-    _G.require = original_require
+    rawset(_G, "require", original_require)
     build_bridge = (socket and build_socket_bridge) or build_file_bridge
     set_insecure_environment = nil
 end