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.
Up to now, on failure the sanei_magic_rotate function returned a
success status. This fixes the following GCC warning:
warning: variable 'ret' set but not used