refs #4871 use gcov47 when possible

git-svn-id: file:///svn/toku/tokudb@46020 c7de825b-a66e-492c-adef-691d508d4ae1

cmake_modules/TokuSetupCompiler.cmake

@@ -30,6 +30,7 @@ if (USE_GCOV)
   if (NOT CMAKE_CXX_COMPILER_ID MATCHES GNU)
     message(FATAL_ERROR "Must use the GNU compiler to compile for test coverage.")
   endif ()
+  find_path(COVERAGE_COMMAND NAMES gcov47 gcov)
 endif (USE_GCOV)
 
 include(CheckCCompilerFlag)