[polly] Fix up regression test config with current features.

Primarily, configure substitutions so we can copy-paste the "RUN" line
of failed tests without worrying about the paths.

polly/test/lit.cfg

@@ -8,6 +8,8 @@ import subprocess
 import lit.formats
 import lit.util
 
+from lit.llvm import llvm_config
+
 # Configuration file for the 'lit' test runner.
 
 # name: The name of this test suite.
@@ -38,6 +40,11 @@ path = os.path.pathsep.join((config.llvm_libs_dir,
                               config.environment.get('LD_LIBRARY_PATH','')))
 config.environment['LD_LIBRARY_PATH'] = path
 
+llvm_config.use_default_substitutions()
+
+tool_patterns = ['opt', 'polly-isl-test']
+llvm_config.add_tool_substitutions(tool_patterns)
+
 # opt knows whether it is compiled with -DNDEBUG.
 import subprocess
 try:

polly/test/lit.site.cfg.in

@@ -1,5 +1,5 @@
-## Autogenerated by LLVM/Polly configuration.
-# Do not edit!
+@LIT_SITE_CFG_IN_HEADER@
+
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
@@ -66,5 +66,8 @@ else:
 if config.enable_gpgpu_codegen == 'TRUE' :
     config.available_features.add('pollyacc')
 
+import lit.llvm
+lit.llvm.initialize(lit_config, config)
+
 # Let the main config do the real work.
 lit_config.load_config(config, "@POLLY_SOURCE_DIR@/test/lit.cfg")