build: reduce one level of spawning in node_gyp

`configure` will now call `node_gyp` as a module instead of forking
makes it easier to debug

PR-URL: https://github.com/nodejs/node/pull/12653
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

configure

@@ -40,6 +40,7 @@ import nodedownload
 # imports in tools/
 sys.path.insert(0, os.path.join(root_dir, 'tools'))
 import getmoduleversion
+from gyp_node import run_gyp
 
 # parse our options
 parser = optparse.OptionParser()
@@ -1380,7 +1381,7 @@ config = '\n'.join(map('='.join, config.iteritems())) + '\n'
 
 write('config.mk', do_not_edit + config)
 
-gyp_args = [sys.executable, 'tools/gyp_node.py', '--no-parallel']
+gyp_args = ['--no-parallel']
 
 if options.use_xcode:
   gyp_args += ['-f', 'xcode']
@@ -1399,4 +1400,4 @@ gyp_args += args
 if warn.warned:
   warn('warnings were emitted in the configure phase')
 
-sys.exit(subprocess.call(gyp_args))
+run_gyp(gyp_args)

tools/gyp_node.py

@@ -13,14 +13,6 @@ import gyp
 output_dir = os.path.join(os.path.abspath(node_root), 'out')
 
 def run_gyp(args):
-  rc = gyp.main(args)
-  if rc != 0:
-    print 'Error running GYP'
-    sys.exit(rc)
-
-if __name__ == '__main__':
-  args = sys.argv[1:]
-
   # GYP bug.
   # On msvs it will crash if it gets an absolute path.
   # On Mac/make it will crash if it doesn't get an absolute path.
@@ -63,5 +55,11 @@ if __name__ == '__main__':
   args.append('-Dlinux_use_bundled_gold=0')
   args.append('-Dlinux_use_gold_flags=0')
 
-  gyp_args = list(args)
-  run_gyp(gyp_args)
+  rc = gyp.main(args)
+  if rc != 0:
+    print 'Error running GYP'
+    sys.exit(rc)
+
+
+if __name__ == '__main__':
+  run_gyp(sys.argv[1:])