title: Can I tell lldb to use a Python other than the first on the PATH?
body: <p>I'm working on adding some Python scripting in my lldb sessions, but I've found that it only works when <code>/usr/bin/python</code> is the first Python on the PATH.  If I have another Python that is found first on the PATH then as soon as lldb initializes its internal Python system it will get an exception like the following and terminate.</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 548, in &lt;module&gt;
      main()
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 530, in main
      known_paths = addusersitepackages(known_paths)
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 266, in addusersitepackages
      user_site = getusersitepackages()
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 241, in getusersitepackages
      user_base = getuserbase() # this will also set USER_BASE
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site.py", line 231, in getuserbase
      USER_BASE = get_config_var('userbase')
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sysconfig.py", line 516, in get_config_var
      return get_config_vars().get(name)
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sysconfig.py", line 449, in get_config_vars
      import re
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 105, in &lt;module&gt;
      import sre_compile
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sre_compile.py", line 14, in &lt;module&gt;
      import sre_parse
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sre_parse.py", line 17, in &lt;module&gt;
      from sre_constants import *
    File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/sre_constants.py", line 18, in &lt;module&gt;
      from _sre import MAXREPEAT
  ImportError: cannot import name MAXREPEAT
  </code></pre>
  
  <p>Is there some lldb setting or command that will let me leave my PATH alone but still have lldb use <code>/usr/bin/python</code>?  </p>
  
  <p>I can also work around the issue by setting <code>PYTHONHOME=/usr</code>, but since I am debugging custom Python builds and Python extensions I would really like to not need to alter the environment.  It seems that there should be some way like <code>settings set internal-python /usr/bin/python</code> that I could put in my <code>~/.lldbinit</code> to tell lldb what to use.</p>