build: simplify `if` in setting of arg_paths

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

tools/gyp_node.py

@@ -16,16 +16,11 @@ def run_gyp(args):
   # 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.
-  if sys.platform == 'win32':
+  a_path = node_root if sys.platform == 'win32' else os.path.abspath(node_root)
-    args.append(os.path.join(node_root, 'node.gyp'))
+  args.append(os.path.join(a_path, 'node.gyp'))
-    common_fn  = os.path.join(node_root, 'common.gypi')
+  common_fn = os.path.join(a_path, 'common.gypi')
-    options_fn = os.path.join(node_root, 'config.gypi')
+  options_fn = os.path.join(a_path, 'config.gypi')
-    options_fips_fn = os.path.join(node_root, 'config_fips.gypi')
+  options_fips_fn = os.path.join(a_path, 'config_fips.gypi')
-  else:
-    args.append(os.path.join(os.path.abspath(node_root), 'node.gyp'))
-    common_fn  = os.path.join(os.path.abspath(node_root), 'common.gypi')
-    options_fn = os.path.join(os.path.abspath(node_root), 'config.gypi')
-    options_fips_fn = os.path.join(os.path.abspath(node_root), 'config_fips.gypi')
 
   if os.path.exists(common_fn):
     args.extend(['-I', common_fn])