cmake: update to work with recent upstream googletest build changes

Summary:
Previously to use gmock you simply needed to link against libgmock_main.
However, googletest pull request #1339 was recently merged into upstream
googletest: https://github.com/google/googletest/pull/1339

These changes now require explicitly linking against libgmock_main, libgmock,
and libgtest.

Reviewed By: yfeldblum

Differential Revision: D6794709

fbshipit-source-id: 03dcccec966e62240987ee0051dfa87be8614cca

CMake/FindGMock.cmake

@@ -3,10 +3,9 @@
 #
 #  LIBGMOCK_DEFINES     - List of defines when using libgmock.
 #  LIBGMOCK_INCLUDE_DIR - where to find gmock/gmock.h, etc.
-#  LIBGMOCK_LIBRARY     - List of libraries when using libgmock.
+#  LIBGMOCK_LIBRARIES   - List of libraries when using libgmock.
 #  LIBGMOCK_FOUND       - True if libgmock found.
 
-
 IF (LIBGMOCK_INCLUDE_DIR)
   # Already in cache, be silent
   SET(LIBGMOCK_FIND_QUIETLY TRUE)
@@ -14,16 +13,42 @@ ENDIF ()
 
 FIND_PATH(LIBGMOCK_INCLUDE_DIR gmock/gmock.h)
 
-FIND_LIBRARY(LIBGMOCK_LIBRARY gmock_main)
+FIND_LIBRARY(LIBGMOCK_MAIN_LIBRARY gmock_main)
+FIND_LIBRARY(LIBGMOCK_LIBRARY gmock)             
+FIND_LIBRARY(LIBGTEST_LIBRARY gtest)
+set(LIBGMOCK_LIBRARIES
+  ${LIBGMOCK_MAIN_LIBRARY}
+  ${LIBGMOCK_LIBRARY}
+  ${LIBGTEST_LIBRARY}
+)
 
-# There isn't currently an easy way to determine if a library was compiled as
-# a shared library on Windows, so just assume we've been built against a shared
-# build of gmock for now.
-SET(LIBGMOCK_DEFINES "GTEST_LINKED_AS_SHARED_LIBRARY=1" CACHE STRING "")
+if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+  # The GTEST_LINKED_AS_SHARED_LIBRARY macro must be set properly on Windows.
+  #
+  # There isn't currently an easy way to determine if a library was compiled as
+  # a shared library on Windows, so just assume we've been built against a
+  # shared build of gmock for now.
+  SET(LIBGMOCK_DEFINES "GTEST_LINKED_AS_SHARED_LIBRARY=1" CACHE STRING "")
+endif()
 
 # handle the QUIETLY and REQUIRED arguments and set LIBGMOCK_FOUND to TRUE if
 # all listed variables are TRUE
 INCLUDE(FindPackageHandleStandardArgs)
-FIND_PACKAGE_HANDLE_STANDARD_ARGS(LIBGMOCK DEFAULT_MSG LIBGMOCK_DEFINES LIBGMOCK_LIBRARY LIBGMOCK_INCLUDE_DIR)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(
+  LIBGMOCK
+  DEFAULT_MSG
+  LIBGMOCK_MAIN_LIBRARY
+  LIBGMOCK_LIBRARY
+  LIBGTEST_LIBRARY
+  LIBGMOCK_LIBRARIES
+  LIBGMOCK_INCLUDE_DIR
+)
 
-MARK_AS_ADVANCED(LIBGMOCK_DEFINES LIBGMOCK_LIBRARY LIBGMOCK_INCLUDE_DIR)
+MARK_AS_ADVANCED(
+  LIBGMOCK_DEFINES
+  LIBGMOCK_MAIN_LIBRARY
+  LIBGMOCK_LIBRARY
+  LIBGTEST_LIBRARY
+  LIBGMOCK_LIBRARIES
+  LIBGMOCK_INCLUDE_DIR
+)

CMakeLists.txt

@@ -340,7 +340,7 @@ if (BUILD_TESTS)
       Boost::thread
       follybenchmark
       folly
-      ${LIBGMOCK_LIBRARY}
+      ${LIBGMOCK_LIBRARIES}
   )
   apply_folly_compile_options_to_target(folly_test_support)