inital code drop.

build/external/premake_external.lua

@@ -0,0 +1,28 @@
+function download_progress(total, current)
+    local ratio = current / total;
+    ratio = math.min(math.max(ratio, 0), 1);
+    local percent = math.floor(ratio * 100);
+    print("Download progress (" .. percent .. "%/100%)")
+end
+
+function check_raylib()
+    os.chdir("external")
+    if(os.isdir("raylib-master") == false) then
+        if(not os.isfile("raylib-master.zip")) then
+            print("Raylib not found, downloading from github")
+            local result_str, response_code = http.download("https://github.com/raysan5/raylib/archive/refs/heads/master.zip", "raylib-master.zip", {
+                progress = download_progress,
+                headers = { "From: Premake", "Referer: Premake" }
+            })
+        end
+        print("Unzipping to " ..  os.getcwd())
+        zip.extract("raylib-master.zip", os.getcwd())
+        os.remove("raylib-master.zip")
+    end
+    os.chdir("../")
+end
+
+function build_externals()
+     print("calling externals")
+     check_raylib()
+end