Issues addressed: 1. Instances of `goto` removed; 2. `-W-unused-parameter` warnings silenced; 3. Calls to `pcre_free()` and `regfree()` inserted; 4. Memory leaks from calling `Strndup()` without freeing previous allocations fixed. [csvgrep_patch.txt](https://github.com/rgamble/csvutils/files/661437/csvgrep_patch.txt)