Add CONFIG_GCOV support to CMake build.

Change-Id: I3925a29737314554ec5821f1123f0e73e46a8128

build/cmake/aom_config_defaults.cmake

diff --git a/build/cmake/aom_config_defaults.cmake b/build/cmake/aom_config_defaults.cmake
index b9c5392..cbc00c8 100644
--- a/build/cmake/aom_config_defaults.cmake
+++ b/build/cmake/aom_config_defaults.cmake
@@ -55,7 +55,6 @@
 set(CONFIG_DEPENDENCY_TRACKING 1 CACHE NUMBER "Deprecated flag.")
 set(CONFIG_EXPERIMENTAL 0 CACHE NUMBER "Deprecated flag.")
 set(CONFIG_EXTERNAL_BUILD 0 CACHE NUMBER "Deprecated flag.")
-set(CONFIG_GCOV 0 CACHE NUMBER "Deprecated flag.")
 set(CONFIG_GPROF 0 CACHE NUMBER "Deprecated flag.")
 set(CONFIG_INSTALL_BINS 0 CACHE NUMBER "Deprecated flag.")
 set(CONFIG_INSTALL_DOCS 0 CACHE NUMBER "Deprecated flag.")
@@ -73,6 +72,7 @@
 set(CONFIG_AV1_ENCODER 1 CACHE NUMBER "Enable AV1 encoder.")
 set(CONFIG_BIG_ENDIAN 0 CACHE NUMBER "Internal flag.")
 set(CONFIG_GCC 0 CACHE NUMBER "Building with GCC (detected).")
+set(CONFIG_GCOV 0 CACHE NUMBER "Enable gcov support.")
 set(CONFIG_LIBYUV 1 CACHE NUMBER "Enables libyuv scaling/conversion support.")
 set(CONFIG_MSVS 0 CACHE NUMBER "Building with MS Visual Studio (detected).")
 set(CONFIG_MULTITHREAD 1 CACHE NUMBER "Multithread support.")

build/cmake/aom_configure.cmake

diff --git a/build/cmake/aom_configure.cmake b/build/cmake/aom_configure.cmake
index 4d007a8..dfb49de 100644
--- a/build/cmake/aom_configure.cmake
+++ b/build/cmake/aom_configure.cmake
@@ -291,6 +291,11 @@
    endif()
 endif()
 
+if (CONFIG_GCOV)
+  message("--- Testing for CONFIG_GCOV support.")
+  require_flag("-fprofile-arcs -ftest-coverage" YES)
+endif ()
+
 if (NOT MSVC)
   aom_push_var(CMAKE_REQUIRED_LIBRARIES "m")
   aom_check_c_compiles("fenv_check"