[CMake] External compiler-rt-configure requires LLVMTestingSupport when including tests

Summary:
Apparently `LLVMTestingSupport` must be built before `llvm-config` can be asked for it. Symptom with `LLVM_INCLUDE_TESTS=ON` is:
```
$ ./path/to/llvm-build/bin/llvm-config --ldflags --libs testingsupport
-L/path/to/llvm-build/lib -Wl,-search_paths_first -Wl,-headerpad_max_install_names
llvm-config: error: component libraries and shared library

llvm-config: error: missing: /path/to/llvm-build/lib/libLLVMTestingSupport.a
```

With `LLVMTestingSupport` as dependency of `compiler-rt-configure` we get the expected behavior:
```
$ ./path/to/llvm-build/bin/llvm-config --ldflags --libs testingsupport
-L/path/to/llvm-build/lib -Wl,-search_paths_first -Wl,-headerpad_max_install_names
-lLLVMTestingSupport -lLLVMSupport -lLLVMDemangle
```

Reviewers: ab, beanz

Subscribers: dberris, mgorny, erik.pilkington, llvm-commits, cfe-commits

Differential Revision: https://reviews.llvm.org/D57521

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@352881 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 2 deletions

diff --git a/runtime/CMakeLists.txt b/runtime/CMakeLists.txt
index 6f453f96d7..0bb0a0aea3 100644
--- a/runtime/CMakeLists.txt
+++ b/runtime/CMakeLists.txt
@@ -58,12 +58,16 @@ if(LLVM_BUILD_EXTERNAL_COMPILER_RT AND EXISTS ${COMPILER_RT_SRC_ROOT}/)
     endif()
   endforeach()
 
+  set(compiler_rt_configure_deps)
   if(TARGET cxx-headers)
-    set(COMPILER_RT_LIBCXX_DEPENDENCY "cxx-headers")
+    list(APPEND compiler_rt_configure_deps "cxx-headers")
+  endif()
+  if(LLVM_INCLUDE_TESTS)
+    list(APPEND compiler_rt_configure_deps LLVMTestingSupport)
   endif()
 
   ExternalProject_Add(compiler-rt
-    DEPENDS llvm-config clang ${COMPILER_RT_LIBCXX_DEPENDENCY}
+    DEPENDS llvm-config clang ${compiler_rt_configure_deps}
     PREFIX ${COMPILER_RT_PREFIX}
     SOURCE_DIR ${COMPILER_RT_SRC_ROOT}
     STAMP_DIR ${STAMP_DIR}