cmake warning regarding gflags

[nickdesaulniers]

$ cmake -G Ninja  -DCMAKE_INSTALL_PREFIX=. -DLLVM_PATH=/android0/llvm-project/llvm/build ..
...
CMake Warning at third_party/glog/CMakeLists.txt:63 (find_package):
  By not providing "Findgflags.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "gflags", but
  CMake did not find one.

  Could not find a package configuration file provided by "gflags" (requested
  version 2.2.0) with any of the following names:

    gflagsConfig.cmake
    gflags-config.cmake

  Add the installation prefix of "gflags" to CMAKE_PREFIX_PATH or set
  "gflags_DIR" to a directory containing one of the above files.  If "gflags"
  provides a separate development package or SDK, be sure it has been
  installed.

[nickdesaulniers]

not sure if related, but cmake later fails with:

CMake Error at third_party/googletest/googletest/cmake/internal_utils.cmake:150 (add_library):
  add_library cannot create target "gtest" because an imported target with
  the same name already exists.
Call Stack (most recent call first):
  third_party/googletest/googletest/cmake/internal_utils.cmake:206 (cxx_library_with_type)
  third_party/googletest/googletest/CMakeLists.txt:128 (cxx_library)


CMake Error at third_party/googletest/googletest/cmake/internal_utils.cmake:150 (add_library):
  add_library cannot create target "gtest_main" because an imported target
  with the same name already exists.
Call Stack (most recent call first):
  third_party/googletest/googletest/cmake/internal_utils.cmake:206 (cxx_library_with_type)
  third_party/googletest/googletest/CMakeLists.txt:130 (cxx_library)


CMake Error at third_party/googletest/googletest/CMakeLists.txt:143 (target_link_libraries):
  Cannot specify link libraries for target "gtest_main" which is not built by
  this project.

[nickdesaulniers]

I rebuilt LLVM itself with the additional cmake flags -DLLVM_INCLUDE_TESTS=OFF -DLLVM_ENABLE_RTTI=ON (that I don't typically use) based on this tip. I still saw the warning regarding gflags, but cmake did complete without the previously observed errors regarding gtest.