Clang generates more warning messages, such as pointing out a lack
of newline at end of file and issues with the size of a strncopy.
Moving -Wno-unused-parameter to the end of the flags avoids it being
overwritten by -Wextra.
Removing -Werror avoids compilation errors that may arise from new
compiler warnings that might come from newer versions of compilers.
This allows the user to specify a different directory to store static files, such as
translations and other resources.
Signed-off-by: Roosembert Palacios <roosembert.palacios@epfl.ch>