Set executable permissions when extracting packages

Packages with .no-sublime-package may contain native executables or
shell scripts, but python's ZipFile implementation doesn't understand
executable permissions.

Fixes #1348

package_control/package_manager.py

@@ -9,6 +9,7 @@
 import tempfile
 # To prevent import errors in thread with datetime
 import locale  # noqa
+from stat import S_IXUSR
 
 try:
     # Python 3
@@ -54,6 +55,9 @@
 ])
 
 
+ZIP_UNIX_SYSTEM = 3
+
+
 class PackageManager():
 
     """
@@ -1393,6 +1397,11 @@ def add_extracted_dirs(dir_):
                             ''',
                             package_name
                         )
+                    else:
+                        # Apply executable permissions
+                        if (info.create_system == ZIP_UNIX_SYSTEM
+                                and (info.external_attr >> 16) & S_IXUSR):
+                            os.chmod(dest, os.stat(dest).st_mode | S_IXUSR)
 
             package_zip.close()
             package_zip = None