CMake: enable reuse of LLVM's googletest src and targets

Fixes an issue that occurs with USE_CMAKE_FIND_PACKAGE_LLVM=ON
and LLVM compiled from sources, which then exports gtest and
gtest_main targets.

In case gtest and gtest_main targets are not imported from LLVM
and GTEST_SRC_DIR is not set, CMake can now reuse the googletest
sources from LLVM_BUILD_MAIN_SRC_DIR (if available) with
USE_CMAKE_FIND_PACKAGE_LLVM=ON. This last limitation is due to
LLVM making modifications to the CMakeLists.txt of googletest
that requires add_llvm_library() from AddLLVM.cmake.

0 files changed, 0 insertions, 0 deletions