Building Ceph v10.2.3 with "make" may kill the compiling system
Ceph v10.2.3 src/Makefile calls the rocksdb static_lib target with "make -j$(shell nproc)". If the "nproc" command does not exist, this becomes "make -j" which quickly overwhelms most systems into a state where they will never recover.
Attempting to override the user's preferences for parallel build is a bad idea, especially when it is done poorly.
Attached is a patch that removes this.