build, win: make LTCG optional

Disables Link Time Code Generation by default. Adds ‘ltcg’ vcbuild
option to enable it. LTCG will be used by default by release and CI
builds.

PR-URL: https://github.com/nodejs/node/pull/21186
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/configure b/configure
index f72e9123b9..1b3ff0162f 100755
--- a/configure
+++ b/configure
@@ -425,6 +425,11 @@ intl_optgroup.add_option('--with-icu-source',
     dest='with_icu_source',
     help='Intl mode: optional local path to icu/ dir, or path/URL of icu source archive.')
 
+parser.add_option('--with-ltcg',
+    action='store_true',
+    dest='with_ltcg',
+    help='Use Link Time Code Generation. This feature is only available on Windows.')
+
 intl_optgroup.add_option('--download',
     action='store',
     dest='download_list',
@@ -953,6 +958,10 @@ def configure_node(o):
   else:
     o['variables']['node_use_perfctr'] = 'false'
 
+  o['variables']['node_with_ltcg'] = b(options.with_ltcg)
+  if flavor != 'win' and options.with_ltcg:
+    raise Exception('Link Time Code Generation is only supported on Windows.')
+
   if options.tag:
     o['variables']['node_tag'] = '-' + options.tag
   else: