Right. "make clean" should fix.
Libleveldb.a and libmememv.a could get stuck. Suggest to run "male clean",also delete build folder and rebuild.
Or as trick,when compiling wallets in windows,got several time stuck on leveldb, even after "TARGET_OS=NATIVE_WINDOWS make libleveldb.a libmemenv.a" command.
90% times got success copyng the entire leveldb from original ones.
If you still got stuck building your pool, i could send you original compiled "ohmygodd" files. Surely it will work. It's linux native.