fix: silence clang warnings in stb_image_resize.h

[vmobilis]

Summary

Clang complains about unused expressions:

stb_image_resize.h:2390:90: warning: expression result unused [-Wunused-value]
 2390 |         STBIR__DEBUG_ASSERT((size_t)STBIR__NEXT_MEMPTR(info->ring_buffer, unsigned char) == (size_t)tempmem + tempmem_size_in_bytes);
      |                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
35 warnings generated.

Related Issue / Discussion

#614

Additional Information

When STBIR_DEBUG is not defined, STBIR__DEBUG_ASSERT is set to "", which causes STBIR__DEBUG_ASSERT(...) to be expanded as (...) – to unused expression.

Adding STBIR__DEBUG_ASSERT(x) blanks the whole assertion.

Or please update https://github.com/nothings/stb/blob/master/deprecated/stb_image_resize.h to version 0.97.
It seems to be stable enough and author replaced debug assertions with regular ones.
(But he changed the license in 0.97).

Checklist

• I have read and confirmed this PR follows the contribution guidelines.