Bug 1620744 - Convert dumpsymbols.py to py3; r=firefox-build-system-reviewers,rstewart

Differential Revision: https://phabricator.services.mozilla.com/D65856

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

config/rules.mk

@@ -702,7 +702,7 @@ define syms_template
 syms:: $(2)
 $(2): $(1)
 ifdef MOZ_CRASHREPORTER
-	$$(call py_action,dumpsymbols,$$(abspath $$<) $$(abspath $$@) $$(DUMP_SYMBOLS_FLAGS))
+	$$(call py3_action,dumpsymbols,$$(abspath $$<) $$(abspath $$@) $$(DUMP_SYMBOLS_FLAGS))
 endif
 endef
 

python/mozbuild/mozbuild/action/dumpsymbols.py

@@ -80,8 +80,8 @@ def dump_symbols(target, tracking_file, count_ctors=False):
     if count_ctors:
         args.append('--count-ctors')
     print('Running: %s' % ' '.join(args))
-    out_files = subprocess.check_output(args)
-    with open(tracking_file, 'w') as fh:
+    out_files = subprocess.check_output(args, universal_newlines=True)
+    with open(tracking_file, 'w', encoding='utf-8', newline='\n') as fh:
         fh.write(out_files)
         fh.flush()