build: add configure option to debug only Node.js part of the binary

Building Node.js with `--debug` takes a long time and generates
binaries that can be hard to work with due to their size, in
particular because debug builds of V8 are large.

Sometimes, it’s sufficient to build the Node.js parts with native
debugging options enabled. Add an option for that.

PR-URL: #31644
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: addaleax

configure.py

@@ -88,6 +88,11 @@
     dest='debug',
     help='also build debug build')
 
+parser.add_option('--debug-node',
+    action='store_true',
+    dest='debug_node',
+    help='build the Node.js part of the binary with debugging symbols')
+
 parser.add_option('--dest-cpu',
     action='store',
     dest='dest_cpu',
@@ -964,6 +969,7 @@ def configure_node(o):
   o['variables']['node_prefix'] = options.prefix
   o['variables']['node_install_npm'] = b(not options.without_npm)
   o['variables']['node_report'] = b(not options.without_report)
+  o['variables']['debug_node'] = b(options.debug_node)
   o['default_configuration'] = 'Debug' if options.debug else 'Release'
 
   host_arch = host_arch_win() if os.name == 'nt' else host_arch_cc()

node.gypi

@@ -272,6 +272,16 @@
         ],
       },
     }],
+    [ 'debug_node=="true"', {
+      'cflags!': [ '-O3' ],
+      'cflags': [ '-g', '-O0' ],
+      'defines': [ 'DEBUG' ],
+      'xcode_settings': {
+        'OTHER_CFLAGS': [
+          '-g', '-O0'
+        ],
+      },
+    }],
     [ 'coverage=="true" and node_shared=="false" and OS in "mac freebsd linux"', {
       'cflags!': [ '-O3' ],
       'ldflags': [ '--coverage',