Declare local variables

[dcooper16]

This PR adds missing declarations for local variables, so that they are not mistakenly treated as globals. It also changes one global variable (single_cipher) to uppercase and deletes two lines in run_cipher_match() that were not doing anything.

What is your pull request about?

• Bug fix
• Improvement
• New feature (adds functionality)
• Breaking change: bug fix, feature or improvement that would cause existing output (especially JSON, CSV) to not work as expected before
• Typo / spelling fix
• Documentation update
• Update of other files

If it's a code change please check the boxes which are applicable

• For the main program: My edits contain no tabs, indentation is five spaces and any line endings do not contain any blank chars
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• My code follows Coding_Convention.md
• I have tested this fix or improvement against >=2 hosts and I couldn't spot a problem
• I have tested this new feature against >=2 hosts which show this feature and >=2 host which does not (in order to avoid side effects) . I couldn't spot a problem
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AI section

• I found a bug / an improvement using LLM version: [e.g. GPT-A.B, Claude <NAME> A.B, Gemini A.B <NAME>, Qwen<B>-Coder, DeepSeek-<A> etc.]
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