Adjust libc++ test infastructure to fully support modules

This patch overhalls the libc++ test format/configuration in order to fully support modules. By "fully support" I mean get almost all of the tests passing. The main hurdle for doing this is handling tests that `#define _LIBCPP_FOO` macros to test a different configuration. This patch deals with these tests in the following ways:

1. For tests that define single `_LIBCPP_ABI_FOO` macros have been annotated with `// MODULES_DEFINES: _LIBCPP_ABI_FOO`. This allows the test suite to define the macro on the command line so it uses a different set of modules.
2. Tests for libc++'s debug mode (which define custom `_LIBCPP_ASSERT`) are automatically detected by the test suite and are compiled and run with modules disabled.

This patch also cleans up how the `CXXCompiler` helper class handles enabling/disabling language features.

NOTE: This patch uses `LIT` features which were only committed to LLVM today. If this patch breaks running the libc++ tests you probably need to update LLVM.
llvm-svn: 288728

1 files changed, 1 insertions, 1 deletions

diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index 47ee972a771..b050e5a5974 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -389,7 +389,7 @@ module std [system] {
   }
   module strstream {
     header "strstream"
-    requires !cplusplus11
+    export *
   }
   module system_error {
     header "system_error"