Suspicious warnings about unused variables

[mloskot]

These seem to be just some left-overs, but some may actually be unused by mistake. I'd appreciate if you could have a look @simmplecoder

test/core/rasterization/circle.cpp:22:20: warning: unused variable ‘r_squared’ [-Wunused-variable]
   22 |     std::ptrdiff_t r_squared = radius * radius;
      |                    ^~~~~~~~~

../../boost/gil/image_processing/hough_transform.hpp:90:16: warning: unused variable ‘width’ [-Wunused-variable]
   90 |     const auto width = input.width();
      |                ^~~~~
../../boost/gil/image_processing/hough_transform.hpp:91:16: warning: unused variable ‘height’ [-Wunused-variable]
   91 |     const auto height = input.height();
      |                ^~~~~~

../../boost/gil/image_processing/diffusion.hpp:155:14: warning: unused variable ‘first’ [-Wunused-variable]
  155 |         auto first = stencil.begin();
      |              ^~~~~
../../boost/gil/image_processing/diffusion.hpp:156:14: warning: unused variable ‘last’ [-Wunused-variable]
  156 |         auto last = stencil.end();
      |              ^~~~

• Compiler version: GCC 9
• Build settings: b2 toolset=gcc cxxstd=11
• Version (Git ref or <boost/version.hpp>): develop

[striezel]

@mloskot: Those warnings already have been removed in the following commits:

• commit 2db5fe9f448bbf4b9da0e38414a366ec5188c817 for circle.cpp
• commit 0b24f4cdbf430430b5430507822b0698cd9d2ac7 for hough_transform.hpp, and
• commit 5dcdf53c02f6b646703b03670c66596beae905ab for diffusion.hpp (see #635)

In other words: I believe this issue is resolved and can be closed.

[mloskot]

Nice, thanks!