cmake/modules/BuildRocksDB.cmake: use string(APPEND ..) when appropriate

less repeatings this way.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>
(cherry picked from commit 620b68a348f07145c49c12668576a89dee8198cb)

diff --git a/cmake/modules/BuildRocksDB.cmake b/cmake/modules/BuildRocksDB.cmake
index 58ce26a6acaf6ed6e26fdb0926063acfa730adf4..01b4ef0e31c85bdd71c45ed7af772df54c2a6702 100644 (file)
--- a/cmake/modules/BuildRocksDB.cmake
+++ b/cmake/modules/BuildRocksDB.cmake
@@ -57,11 +57,11 @@ function(build_rocksdb)
   include(CheckCXXCompilerFlag)
   check_cxx_compiler_flag("-Wno-deprecated-copy" HAS_WARNING_DEPRECATED_COPY)
   if(HAS_WARNING_DEPRECATED_COPY)
-    set(rocksdb_CXX_FLAGS -Wno-deprecated-copy)
+    string(APPEND rocksdb_CXX_FLAGS " -Wno-deprecated-copy")
   endif()
   check_cxx_compiler_flag("-Wno-pessimizing-move" HAS_WARNING_PESSIMIZING_MOVE)
   if(HAS_WARNING_PESSIMIZING_MOVE)
-    set(rocksdb_CXX_FLAGS "${rocksdb_CXX_FLAGS} -Wno-pessimizing-move")
+    string(APPEND rocksdb_CXX_FLAGS " -Wno-pessimizing-move")
   endif()
   if(rocksdb_CXX_FLAGS)
     list(APPEND rocksdb_CMAKE_ARGS -DCMAKE_CXX_FLAGS='${rocksdb_CXX_FLAGS}')