Make build.bat a python script

tools/build.bat

@@ -1,7 +0,0 @@
-pushd ..\addons\
-del /q /f *.pbo
-for /D %%i in (*.*) do (
-	makepbo -NUP -@=z\addons\ace\%%i %%i ace_%%i.pbo
-	if %errorlevel% neq 0 exit /b %errorlevel%
-)
-popd

tools/build.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+import subprocess
+
+
+def mod_time(path):
+    if not os.path.isdir(path):
+        return os.path.getmtime(path)
+    maxi = os.path.getmtime(path)
+    for p in os.listdir(path):
+        maxi = max(mod_time(os.path.join(path, p)), maxi)
+    return maxi
+
+
+def check_for_changes(addonspath, module):
+    if not os.path.exists(os.path.join(addonspath, "ace_{}.pbo".format(module))):
+        return True
+    return mod_time(os.path.join(addonspath, module)) > mod_time(os.path.join(addonspath, "ace_{}.pbo".format(module)))
+
+
+def main():
+    print("####################")
+    print("# ACE3 Debug Build #")
+    print("####################\n")
+
+    scriptpath = os.path.realpath(__file__)
+    projectpath = os.path.dirname(os.path.dirname(scriptpath))
+    addonspath = os.path.join(projectpath, "addons")
+
+    os.chdir(addonspath)
+
+    made = 0
+    failed = 0
+    skipped = 0
+    for p in os.listdir(addonspath):
+        path = os.path.join(addonspath, p)
+        if not os.path.isdir(path):
+            continue
+        if p[0] == ".":
+            continue
+        if not check_for_changes(addonspath, p):
+            skipped += 1
+            print("Skipping {}.".format(p))
+            continue
+
+        print("# Making {} ...".format(p))
+
+        try:
+            subprocess.check_output([
+                "makepbo",
+                "-NUP",
+                "-@=z\\addons\\ace\\{}".format(p),
+                p,
+                "ace_{}.pbo".format(p)
+            ], stderr=subprocess.STDOUT)
+        except:
+            failed += 1
+            print("  Failed to make {}.".format(p))
+        else:
+            made += 1
+            print("  Successfully made {}.".format(p))
+
+    print("\n# Done.")
+    print("  Made {}, skipped {}, failed to make {}.".format(made, skipped, failed))
+
+
+if __name__ == "__main__":
+    sys.exit(main())