Visual Studio rejects pointer arithmetic and dereferencing of void*

[tautschnig]

Pointer arithmetic using void* is a (document) GCC extension.
Dereferencing void* pointers is permitted by GCC when the value is
unused. Visual Studio rejects both.

Fixes: #5275

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #6674 (674a8f0) into develop (3f9f055) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##           develop    #6674      +/-   ##
===========================================
- Coverage    76.81%   76.81%   -0.01%     
===========================================
  Files         1582     1582              
  Lines       182762   182774      +12     
===========================================
+ Hits        140397   140400       +3     
- Misses       42365    42374       +9     

Impacted Files	Coverage Δ
src/ansi-c/c_typecheck_expr.cpp	76.45% <50.00%> (-0.15%)	⬇️
src/util/signal_catcher.cpp	84.61% <0.00%> (-11.54%)	⬇️

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