[clang] Add abi-breaking-checks support to clang

[mgrang]

Summary

You can now use REQUIRES:abi-breaking-checks in clang too

[mgrang]

The test clang/test/Rewriter/objc-modern-metadata-visibility2.mm is listed as UNSUPPORTED since the test contains REQUIRES:abi-breaking-checks but clang does not support this yet.

[mgrang]

Ping for reviews please.

[mgrang]

Ping 2 for reviews please!

[jroelofs]

LGTM

cfe/trunk/test/lit.cfg

 run_console_tests = int(lit_config.params.get('enable_console', '0'))
 if run_console_tests != 0:
   config.available_features.add('console')
 
 lit.util.usePlatformSdkOnDarwin(config, lit_config)
 macOSSDKVersion = lit.util.findPlatformSdkVersionOnMacOS(config, lit_config)
 if macOSSDKVersion is not None:
     config.available_features.add('macos-sdk-' + macOSSDKVersion)
+
+if config.enable_abi_breaking_checks == "1":
+    config.available_features.add('abi-breaking-checks')

cfe/trunk/test/lit.site.cfg.in

 config.clang_arcmt = @CLANG_ENABLE_ARCMT@
 config.clang_default_cxx_stdlib = "@CLANG_DEFAULT_CXX_STDLIB@"
 config.clang_staticanalyzer = @CLANG_ENABLE_STATIC_ANALYZER@
 config.clang_staticanalyzer_z3 = "@CLANG_ANALYZER_WITH_Z3@"
 config.clang_examples = @CLANG_BUILD_EXAMPLES@
 config.enable_shared = @ENABLE_SHARED@
 config.enable_backtrace = @ENABLE_BACKTRACES@
 config.host_arch = "@HOST_ARCH@"
+config.enable_abi_breaking_checks = "@LLVM_ENABLE_ABI_BREAKING_CHECKS@"
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.
 try:
     config.clang_tools_dir = config.clang_tools_dir % lit_config.params
     config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
     config.llvm_shlib_dir = config.llvm_shlib_dir % lit_config.params
     config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
 except KeyError:
     e = sys.exc_info()[1]
     key, = e.args
     lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@CLANG_SOURCE_DIR@/test/lit.cfg")