These were intended to suppress GCC warnings about unused variables.
However, this leads to different warnings from Clang instead.
Use another approach that suppresses warnings from both compilers.
With the exception of use in three quotes as well as our inlcuded copy
of the GPL, all use of the Free Software Foundation's postal address
has been removed.
Re #320.
Source code was inconsistent on how they were referencing
include files in include/sane. In certain cases, sane/sane.h
and sane/saneopts.h was really including external copies (with
some preprocessor implementations anyways).