diff --git a/build.py b/build.py
index c7aeb8ac..335f2602 100644
--- a/build.py
+++ b/build.py
@@ -45,6 +45,8 @@ def parse_args():
         help="Generate .pot files from source code.")
     parser.add_option('--mergepot', action='store_true', dest='mergepot',
         help="Update all .po files based on .pot files.")
+    parser.add_option('--normpo', action='store_true', dest='normpo',
+        help="Normalize all PO files (do this before commit).")
     (options, args) = parser.parse_args()
     return options
 
@@ -238,6 +240,12 @@ def build_mergepot():
     loc.merge_pots_into_pos(op.join('qtlib', 'locale'))
     loc.merge_pots_into_pos(op.join('cocoalib', 'locale'))
 
+def build_normpo():
+    loc.normalize_all_pos('locale')
+    loc.normalize_all_pos(op.join('hscommon', 'locale'))
+    loc.normalize_all_pos(op.join('qtlib', 'locale'))
+    loc.normalize_all_pos(op.join('cocoalib', 'locale'))
+
 def build_cocoa_proxy_module():
     print("Building Cocoa Proxy")
     import objp.p2o
@@ -339,6 +347,8 @@ def main():
         build_updatepot()
     elif options.mergepot:
         build_mergepot()
+    elif options.normpo:
+        build_normpo()
     elif options.cocoa_ext:
         build_cocoa_proxy_module()
         build_cocoa_bridging_interfaces(edition)
diff --git a/hscommon/loc.py b/hscommon/loc.py
index 9be85bfb..cd6b72ef 100644
--- a/hscommon/loc.py
+++ b/hscommon/loc.py
@@ -77,6 +77,24 @@ def merge_po_and_preserve(source, dest):
         destpo.append(entry)
     destpo.save()
 
+def normalize_all_pos(base_folder):
+    """Normalize the format of .po files in base_folder.
+    
+    When getting POs from external sources, such as Transifex, we end up with spurious diffs because
+    of a difference in the way line wrapping is handled. It wouldn't be a big deal if it happened
+    once, but these spurious diffs keep overwriting each other, and it's annoying.
+    
+    Our PO files will keep polib's format. Call this function to ensure that freshly pulled POs
+    are of the right format before committing them.
+    """
+    langs = get_langs(base_folder)
+    for lang in langs:
+        pofolder = op.join(base_folder, lang, LC_MESSAGES)
+        pofiles = files_with_ext(pofolder, '.po')
+        for pofile in pofiles:
+            p = polib.pofile(pofile)
+            p.save()
+
 #--- Cocoa
 def all_lproj_paths(folder):
     return files_with_ext(folder, '.lproj')