[lit] Disable test on darwin when building shared libs.

Summary:
This test fails to link shared libraries because tries to run
a copied version of clang-check to see if the mock version of libcxx
in the same directory can be loaded dynamically.  Since the test is
specifically designed not to look in the default just-built lib
directory, it must be disabled when building with
BUILD_SHARED_LIBS=ON.

Currently only disabling it on Darwin and basing it on the
enable_shared flag.

Reviewed By: ilya-biryukov

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D61697

llvm-svn: 363298

clang/test/Tooling/clang-check-mac-libcxx-fixed-compilation-db.cpp

@@ -16,5 +16,7 @@
 //
 // ^ -ccc-install-dir passed to unbreak tests on *BSD where
 //   getMainExecutable() relies on real argv[0] being passed
+//
+// UNSUPPORTED: enable_shared
 #include <mock_vector>
 vector v;

llvm/utils/lit/lit/llvm/config.py

@@ -48,6 +48,8 @@ class LLVMConfig(object):
             # We should standardize on the former.
             features.add('system-linker-mach-o')
             features.add('system-darwin')
+            if config.enable_shared:
+                features.add("enable_shared")
         elif platform.system() == 'Windows':
             # For tests that require Windows to run.
             features.add('system-windows')