Lua: Further centralize code, fix Bizhawk 2.9 (#1685)

* Fixes the socket library for bizhawk 2.9/lua 5.4 by including another one in parallel
* Fixes lua 5.4 support by making socket.lua into a "modern" module (the `module` keyword is gone)
* Adds the linux version and 32 bit windows socket dlls because why not
* Merges common functions into `common.lua` - the only functional change of this should be that:
  * Some things that were locals are globals now - this can be changed, I just was lazy and it likely doesn't matter
  * `drawText` now uses middle/bottom for all prints - feel free to do what you like with that change

data/lua/common.lua

@@ -0,0 +1,102 @@
+local lua_major, lua_minor = _VERSION:match("Lua (%d+)%.(%d+)")
+lua_major = tonumber(lua_major)
+lua_minor = tonumber(lua_minor)
+-- lua compat shims
+if lua_major > 5 or (lua_major == 5 and lua_minor >= 3) then
+  require("lua_5_3_compat")
+end
+
+function table.empty (self)
+    for _, _ in pairs(self) do
+        return false
+    end
+    return true
+end
+
+local bizhawk_version = client.getversion()
+local bizhawk_major, bizhawk_minor, bizhawk_patch = bizhawk_version:match("(%d+)%.(%d+)%.?(%d*)")
+bizhawk_major = tonumber(bizhawk_major)
+bizhawk_minor = tonumber(bizhawk_minor)
+if bizhawk_patch == "" then
+  bizhawk_patch = 0
+else
+  bizhawk_patch = tonumber(bizhawk_patch)
+end
+
+local is23Or24Or25 = (bizhawk_version=="2.3.1") or (bizhawk_major == 2 and bizhawk_minor >= 3 and bizhawk_minor <= 5)
+local isGreaterOrEqualTo26 = bizhawk_major > 2 or (bizhawk_major == 2 and bizhawk_minor >= 6)
+local isUntestedBizhawk = bizhawk_major > 2 or (bizhawk_major == 2 and bizhawk_minor > 9)
+local untestedBizhawkMessage = "Warning: this version of bizhawk is newer than we know about. If it doesn't work, consider downgrading to 2.9"
+
+u8 = memory.read_u8
+wU8 = memory.write_u8
+u16 = memory.read_u16_le
+
+function getMaxMessageLength()
+  local denominator = 12
+  if is23Or24Or25 then
+    denominator = 11
+  end
+  return math.floor(client.screenwidth()/denominator)
+end
+
+function drawText(x, y, message, color)
+  if is23Or24Or25 then
+      gui.addmessage(message)
+  elseif isGreaterOrEqualTo26 then
+      gui.drawText(x, y, message, color, 0xB0000000, 18, "Courier New", "middle", "bottom", nil, "client")
+  end
+end
+
+function clearScreen()
+  if is23Or24Or25 then
+      return
+  elseif isGreaterOrEqualTo26 then
+      drawText(0, 0, "", "black")
+  end
+end
+
+itemMessages = {}
+
+function drawMessages()
+  if table.empty(itemMessages) then
+      clearScreen()
+      return
+  end
+  local y = 10
+  found = false
+  maxMessageLength = getMaxMessageLength()
+  for k, v in pairs(itemMessages) do
+      if v["TTL"] > 0 then
+          message = v["message"]
+          while true do
+              drawText(5, y, message:sub(1, maxMessageLength), v["color"])
+              y = y + 16
+
+              message = message:sub(maxMessageLength + 1, message:len())
+              if message:len() == 0 then
+                  break
+              end
+          end
+          newTTL = 0
+          if isGreaterOrEqualTo26 then
+              newTTL = itemMessages[k]["TTL"] - 1
+          end
+          itemMessages[k]["TTL"] = newTTL
+          found = true
+      end
+  end
+  if found == false then
+      clearScreen()
+  end
+end
+
+function checkBizhawkVersion()
+  if not is23Or24Or25 and not isGreaterOrEqualTo26 then
+    print("Must use a version of bizhawk 2.3.1 or higher")
+    return false
+  elseif isUntestedBizhawk then
+    print(untestedBizhawkMessage)
+  end
+  return true
+end