message: gcc 7 could not compile
diff: @@ -2,7 +2,11 @@ CLEAN_FILES = # deliberately empty, so we can append below.
  CXX=g++
  PLATFORM_LDFLAGS= -lpthread -lrt
  PLATFORM_CXXFLAGS= -std=c++11 -fno-builtin-memcmp -msse -msse4.2
  -ROCKSDB_CXXFLAGS= -Wno-error=deprecated-copy -Wno-error=pessimizing-move -Wno-error=class-memaccess -Wno-error=array-bounds
  +ROCKSDB_CXXFLAGS=
  +CC_VERSION_MAJOR := $(shell $(CXX) -dumpversion | cut -d '.' -f1)
  +ifeq (1,$(shell expr $(CC_VERSION_MAJOR) \> 7))
  +ROCKSDB_CXXFLAGS += -Wno-error=deprecated-copy -Wno-error=pessimizing-move -Wno-error=class-memaccess -Wno-error=array-bounds
  +endif
  PROFILING_FLAGS=-pg
  OPT=
  LDFLAGS += -Wl,-rpath=$(RPATH)
  