Bug 1575804 - Don't decode the result from get_cmd_output. r=chmanchester

Also don't pass universal_newlines to check_cmd_output. That was added
to make python 3 happier when check_cmd_output still returned bytes, to
hint subprocess to return a unicode string, but now that
check_cmd_output does the decoding, that's not needed anymore.

Differential Revision: https://phabricator.services.mozilla.com/D43205

--HG--
extra : moz-landing-system : lando

build/moz.configure/init.configure

@@ -789,7 +789,7 @@ def real_host(value, shell):
     if not value:
         config_guess = os.path.join(os.path.dirname(__file__), '..',
                                     'autoconf', 'config.guess')
-        host = check_cmd_output(shell, config_guess, universal_newlines=True).strip()
+        host = check_cmd_output(shell, config_guess).strip()
         try:
             return split_triplet(host)
         except ValueError:

build/moz.configure/toolchain.configure

@@ -2025,22 +2025,20 @@ def select_linker(linker, c_compiler, developer_options, enable_gold,
         env = dict(os.environ)
         env['LD_PRINT_OPTIONS'] = '1'
         retcode, stdout, stderr = get_cmd_output(*cmd, env=env)
-        cmd_output = stdout.decode('utf-8')
-        stderr = stderr.decode('utf-8')
         if retcode == 1 and 'Logging ld64 options' in stderr:
             kind = 'ld64'
 
         elif retcode != 0:
             return None
 
-        elif 'GNU ld' in cmd_output:
+        elif 'GNU ld' in stdout:
             # We are using the normal linker
             kind = 'bfd'
 
-        elif 'GNU gold' in cmd_output:
+        elif 'GNU gold' in stdout:
             kind = 'gold'
 
-        elif 'LLD' in cmd_output:
+        elif 'LLD' in stdout:
             kind = 'lld'
 
         else: