Don't modify the PWD in gyp_v8

build/gyp_v8

Index: build/gyp_v8
diff --git a/build/gyp_v8 b/build/gyp_v8
index 40c377de61581239d6f0d208171553c54fe6b54d..7874d1444eb639bf7f2ff417ef1e76cfee7ca95c 100755
--- a/build/gyp_v8
+++ b/build/gyp_v8
@@ -36,13 +36,8 @@ import platform
 import shlex
 import sys
 
-script_dir = os.path.dirname(__file__)
-v8_root = os.path.normpath(os.path.join(script_dir, os.pardir))
-
-if __name__ == '__main__':
-  os.chdir(v8_root)
-  script_dir = os.path.dirname(__file__)
-  v8_root = '.'
+script_dir = os.path.dirname(os.path.realpath(__file__))
+v8_root = os.path.abspath(os.path.join(script_dir, os.pardir))
 
 sys.path.insert(0, os.path.join(v8_root, 'build', 'gyp', 'pylib'))
 import gyp
@@ -142,10 +137,7 @@ if __name__ == '__main__':
       # path separators even on Windows due to the use of shlex.split().
       args.extend(shlex.split(gyp_file))
     else:
-      # Note that this must not start with "./" or things break.
-      # So we rely on having done os.chdir(v8_root) above and use the
-      # relative path.
-      args.append(os.path.join('build', 'all.gyp'))
+      args.append(os.path.join(script_dir, 'all.gyp'))
 
   args.extend(['-I' + i for i in additional_include_files(args)])