Do not assume that build architecture has byte/char==8 bits

[tautschnig]

The C/C++ standard does not guarantee this, and limits.h/climits has the
CHAR_BIT define set properly.

All changes in this commit only refer to the platform the tool is being
built for. The analysis target requires a separate set of changes where
the byte width must be taken from the configuration or annotations
within expressions.

This is a first part of #917, now factored into a PR of its own.

• 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 #5962 (74978c0) into develop (1c32785) will increase coverage by 0.19%.
The diff coverage is 94.54%.

@@             Coverage Diff             @@
##           develop    #5962      +/-   ##
===========================================
+ Coverage    74.11%   74.30%   +0.19%     
===========================================
  Files         1444     1444              
  Lines       157389   157404      +15     
===========================================
+ Hits        116646   116957     +311     
+ Misses       40743    40447     -296     

Impacted Files	Coverage Δ
src/goto-cc/ms_cl_cmdline.cpp	0.00% <0.00%> (ø)
src/util/config.cpp	55.42% <ø> (ø)
src/util/irep_hash.h	100.00% <ø> (ø)
src/ansi-c/literals/convert_character_literal.cpp	68.29% <50.00%> (+36.58%)	⬆️
src/util/mp_arith.cpp	50.00% <75.00%> (-0.65%)	⬇️
jbmc/src/janalyzer/janalyzer_parse_options.cpp	48.42% <100.00%> (+0.16%)	⬆️
jbmc/src/jbmc/jbmc_parse_options.cpp	72.44% <100.00%> (+0.05%)	⬆️
jbmc/src/jdiff/jdiff_parse_options.cpp	68.79% <100.00%> (+0.22%)	⬆️
src/cbmc/cbmc_parse_options.cpp	76.24% <100.00%> (+0.05%)	⬆️
src/goto-analyzer/goto_analyzer_parse_options.cpp	71.68% <100.00%> (+0.08%)	⬆️
... and 14 more

---

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[martin-cs]

Glad to see you and the author of #5873 managed to sort things out ( #5873 (comment) )

[kroening]

Note that the commit message isn't entirely true: The changes to ansi-c/library/gcc.c affect the analysis platform, not the build platform.

[tautschnig]

Note that the commit message isn't entirely true: The changes to ansi-c/library/gcc.c affect the analysis platform, not the build platform.

Oh, indeed, I've moved those changes to the commit in #917 instead.

[chrisr-diffblue]

Thanks for the cleanup - much better :-)

[chrisr-diffblue]

Out-of-scope for this PR, but give how this exact log.status pattern is duplicated several times, it does rather feel like a utility function could be useful :-)

[tautschnig]

Thank you for highlighting this. Now PR'ed in #6089.