Updating to gnulib pulled in new quote and quotarg modules,
by which quoting is now done like 'this' rather than `this'.
That change induces many "make check" test failures. This change
adapts code and tests so that "make check" passes once again.
* src/scan-code.l: Quote like 'this', not like `this'.
* src/scan-gram.l: Likewise.
* src/symtab.c: Likewise.
* tests/actions.at: Adjust tests to match.
* tests/input.at: Likewise.
* tests/named-refs.at: Likewise.
* tests/output.at: Likewise.
* tests/regression.at: Likewise.
* lib/.gitignore: Regenerate.
* m4/.gitignore: Likewise.