Summary:
Using gcc 5.2.1 to compile RocksDB on Ubuntu 15.10 results in a warning about unused variable. Warning is treated as an error and all of it results in a build break. Fix the issue and make sure that everything compiles with that particular configuration.
P.S. Lint complains about a non-ASCII character used in the source code ("Wagner-Fischer"). Fix this as well.
Test Plan:
# Everything compiler cleanly on the system which exhibited the problem.
# `make clean && make -j 16` on CentOS.
# `make clean && USE_CLANG=1 make -j 16` on CentOS.
Reviewers: sdong, igor
Reviewed By: igor
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D55503
Gunnar Kudrjavets
6b03f93d4f