Merge pull request #23441 from tchaikov/wip-cmake-rocksdb-cleanup

cmake: rocksdb related cleanup

Reviewed-by: Casey Bodley <cbodley@redhat.com>

diff --cc CMakeLists.txt
index 67d258f21ad71d229964de35bd107816fbd64e96,3709830d13272d9ab23a8313b9da70ddbc752b37..dcd6ee393578e38442a649a8ce6f52c1fbfb819c
--- 1/CMakeLists.txt
--- 2/CMakeLists.txt
+++ b/CMakeLists.txt
@@@ -314,9 -314,17 +314,13 @@@ if(WITH_LZ4
  endif(WITH_LZ4)
  
  #if allocator is set on command line make sure it matches below strings
+ set(ALLOCATOR "" CACHE STRING
+   "specify memory allocator to use. currently tcmalloc, tcmalloc_minimal, \
+ jemalloc, and libc is supported. if not specified, will try to find tcmalloc, \
+ and then jemalloc. If neither of then is found. use the one in libc.")
  if(ALLOCATOR)
    if(${ALLOCATOR} MATCHES "tcmalloc(_minimal)?")
 -    if(GPERFTOOLS_USE_STATIC_LIBS)
 -      include(Buildgperftools)
 -    else()
 -      find_package(gperftools REQUIRED)
 -    endif()
 +    find_package(gperftools REQUIRED)
      set(HAVE_LIBTCMALLOC ON)
    elseif(${ALLOCATOR} STREQUAL "jemalloc")
      find_package(JeMalloc REQUIRED)