Ensure objects within library files are sorted (#15780)

We saw an odd issue recently where clearing the cache and rebuilding
generated different result.  Looking that the library files I notices
that orders of the object files with each library did not match.

This change means the order will be fixed regardless of ordering of the
files in the directories of the host machine.

See #15762

Author: sbc100

tools/system_libs.py

@@ -36,7 +36,7 @@ def files_in_path(path, filenames):
 def glob_in_path(path, glob_pattern, excludes=()):
   srcdir = utils.path_from_root(path)
   files = iglob(os.path.join(srcdir, glob_pattern), recursive=True)
-  return [f for f in files if os.path.basename(f) not in excludes]
+  return sorted(f for f in files if os.path.basename(f) not in excludes)
 
 
 def get_base_cflags(force_object_files=False):
@@ -75,6 +75,7 @@ def run_build_commands(commands):
 def create_lib(libname, inputs):
   """Create a library from a set of input objects."""
   suffix = shared.suffix(libname)
+  inputs = sorted(inputs, key=lambda x: os.path.basename(x))
   if suffix in ('.bc', '.o'):
     if len(inputs) == 1:
       if inputs[0] != libname: