tidy-up: syntax and code nits

- cmp-pkg-config.sh: replace `-r -f` with `-rf` to match rest of repo.
- configure.ac: add double quotes for robustness (not a bug).
- curl-openssl.m4: merge nested `if`s.
- CurlTests.c: drop `!= 0`, also to sync with m4.
- CurlTests.c: replace `example.com` with `localhost` in
  `gethostbyname()` feature test code. (compile-only, not a bug)
- GHA/http3-linux: drop literal `true` from bool expression.
- lib650: drop redundant `&`.
- move variable/call to left-hand side of equality checks, where
  missing.
- perl: detach `<`/`>` from filename in `open()`, where missing.
- schannel: apply two nit fixes lost in rebase.
- scripts/verify-release: drop redundant double quotes.
- scripts/verify-release: exit with error code on error.
- synctime: replace magic numbers with `sizeof()`.
- telnet: add missing parentheses to macro value.
- tests/Makefile.am: use single quotes.
- tool_operate: drop redundant `break` after `return` in VMS code.
- unit2413: drop unused NULL pointer + free call.
- unit2413: fix duplicate test case name.
- urlapi: drop redundant parentheses.
- urlapi: drop `CURL_UNCONST()` that became redundant.

Closes #22186

.github/workflows/http3-linux.yml

@@ -219,7 +219,7 @@ jobs:
         run: echo 'needs-build=true' >> "$GITHUB_OUTPUT"
 
       - name: 'install build prereqs'
-        if: ${{ steps.settings.outputs.needs-build == 'true' }}
+        if: ${{ steps.settings.outputs.needs-build }}
         timeout-minutes: 2
         run: |
           sudo find /etc/apt/sources.list.d -type f -not -name 'ubuntu.sources' -delete -print