[lldb/test] Respect --apple-sdk path when querying SDK info

[vsk]

Summary

Respect --apple-sdk <path> if it's specified. If the SDK simply mounted from
some disk image, and not actually installed, this is the only way to use it.

[JDevlieghere]

LGTM

lldb/packages/Python/lldbsuite/test/lldbutil.py

69

This will also exclude the empty string.

[vsk]

lldb/packages/Python/lldbsuite/test/lldbutil.py

69

Thanks, I'll fix this before committing.

lldb/packages/Python/lldbsuite/test/lldbutil.py

 
 # Third-party modules
 from six import StringIO as SixStringIO
 import six
 
 # LLDB modules
 import lldb
 from . import lldbtest_config
+from . import configuration
 
 # How often failed simulator process launches are retried.
 SIMULATOR_RETRY = 3
 
 # ===================================================
 # Utilities for locating/checking executable programs
 # ===================================================
 
if not os.path.isdir(path):
         raise OSError(errno.ENOTDIR, "%s is not a directory"%path)
 
 
 # ============================
 # Dealing with SDK and triples
 # ============================
 
 def get_xcode_sdk(os, env):
+    # Respect --apple-sdk <path> if it's specified. If the SDK is simply
+    # mounted from some disk image, and not actually installed, this is the
+    # only way to use it.
+    if configuration.apple_sdk:
+        return configuration.apple_sdk
     if os == "ios":
         if env == "simulator":
             return "iphonesimulator"
         if env == "macabi":
             return "macosx"
         return "iphoneos"
     elif os == "tvos":
         if env == "simulator":