Update iOS merge script.

talk/build/merge_ios_libs

 #!/usr/bin/python
 #
 # libjingle
 # Copyright 2015 Google Inc.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
 #
 #  1. Redistributions of source code must retain the above copyright notice,
 #     this list of conditions and the following disclaimer.
@@ skipping 43 matching lines @@
   libs = {}
   for dirpath, _, filenames in os.walk(lib_base_dir):
     if dirpath.endswith(output_dir_name):
       continue
     for filename in filenames:
       if not filename.endswith('.a'):
         continue
       entry = libs.get(filename, [])
       entry.append(os.path.join(dirpath, filename))
       libs[filename] = entry
-  # Some sublibaries are only present in certain architectures. We merge
-  # them into their parent library so that the library list is consistent
-  # across architectures.
-  libs_copy = dict(libs)
+
+  orphaned_libs = {}
+  valid_libs = {}
   for library, paths in libs.items():
     if len(paths) < len(archs):
-      # Hacky: we find parent libraries by stripping off each name component.
-      components = library.strip('.a').split('_')[:-1]
-      found = False
-      while components:
-        parent_library = '_'.join(components) + '.a'
-        if (parent_library in libs_copy
-            and len(libs_copy[parent_library]) >= len(archs)):
-          libs[parent_library].extend(paths)
-          del libs[library]
+      orphaned_libs[library] = paths
+    else:
+      valid_libs[library] = paths
+  for library, paths in orphaned_libs.items():
+    components = library[:-2].split('_')[:-1]
+    found = False
+    # Find directly matching parent libs by stripping suffix.
+    while components and not found:
+      parent_library = '_'.join(components) + '.a'
+      if parent_library in valid_libs:
+        valid_libs[parent_library].extend(paths)
+        found = True
+        break
+      components = components[:-1]
+    # Find next best match by finding parent libs with the same prefix.
+    if not found:
+      base_prefix = library[:-2].split('_')[0]
+      for valid_lib, valid_paths in valid_libs.items():
+        prefix = '_'.join(components)
+        if valid_lib[:len(base_prefix)] == base_prefix:
+          valid_paths.extend(paths)
           found = True
           break
-        components = components[:-1]
-      assert found
+    assert found
 
   # Create output directory.
   output_dir_path = os.path.join(lib_base_dir, output_dir_name)
   if not os.path.exists(output_dir_path):
     os.mkdir(output_dir_path)
 
   # Use this so libtool merged binaries are always the same.
   env = os.environ.copy()
   env['ZERO_AR_DATE'] = '1'
 
   # Ignore certain errors.
   libtool_re = re.compile(r'^.*libtool:.*file: .* has no symbols$')
 
   # Merge libraries using libtool.
-  for library, paths in libs.items():
+  for library, paths in valid_libs.items():
     cmd_list = ['libtool', '-static', '-v', '-o',
                 os.path.join(output_dir_path, library)] + paths
     libtoolout = subprocess.Popen(cmd_list, stderr=subprocess.PIPE, env=env)
     _, err = libtoolout.communicate()
     for line in err.splitlines():
       if not libtool_re.match(line):
         print >>sys.stderr, line
     # Unconditionally touch the output .a file on the command line if present
     # and the command succeeded. A bit hacky.
     if not libtoolout.returncode:
       for i in range(len(cmd_list) - 1):
         if cmd_list[i] == '-o' and cmd_list[i+1].endswith('.a'):
           os.utime(cmd_list[i+1], None)
           break
     else:
       return libtoolout.returncode
   return libtoolout.returncode
 
 
 def Main():
   parser = optparse.OptionParser()
   _, args = parser.parse_args()
   if len(args) != 1:
     parser.error('Error: Exactly 1 argument required.')
   lib_base_dir = args[0]
   MergeLibs(lib_base_dir)
 
 if __name__ == '__main__':
   sys.exit(Main())