core: Distinguish invalid size parameters from range errors

[arturobernalg]

ap_size_parameter_parse() (#829) returned APR_ERANGE for a value without any digits (abc, +, -) on libc implementations where strtoll() sets EINVAL when nothing is converted, such as FreeBSD and musl. glibc leaves errno alone there, so the function returned APR_EINVAL, as documented. The result depended on the libc.

When nothing is converted the C library stores the start of the string in the end pointer, so end == parameter tells portably that nothing was converted. Check it before the apr_strtoff() status. APR_EINVAL is for invalid syntax, APR_ERANGE stays for overflow and underflow.

LimitXMLRequestBody (#825) had its own apr_strtoff() parsing and had the same problem, so use the common function there as well. This is the change of #847. No change in the accepted values.

test_core_012_005 checks that LimitRequestBody reports invalid syntax and range errors with their own messages, and LimitXMLRequestBody is added to the directives of test_012. On glibc these tests pass with or without the change; they only catch the problem on FreeBSD and musl.

Tested with trunk at ba3fa29:

• Linux (glibc): test/modules/core 279 passed; for 15 LimitRequestBody values the result is the same as before.
• FreeBSD 14.5-RELEASE VM, test_010 and test_012: 7 failed and 228 passed on trunk, 235 passed with this change.
• ap_size_parameter_parse() alone, with 14 inputs (valid, no digits, trailing characters, overflow, underflow): all correct on glibc and on musl (Alpine 3.17). On musl trunk gets 5 of them wrong.

No CHANGES entry: ap_size_parameter_parse() is trunk only and was never released, and the accepted values do not change.

---

• This PR does not report or address a security vulnerability
  (see SECURITY.md and
  https://www.apache.org/security/#reporting-a-vulnerability).
• Code follows the httpd style guide.
• New log messages (level debug or higher) use an empty APLOGNO() tag;
  numbers are assigned by a committer at merge time (see docs/log-message-tags/README).
  (No new log messages.)
• If the change is user-visible, a changes-entries/*.txt file is included,
  following the template in README.CHANGES (not needed otherwise).
  (Not needed, see above.)
• Test cases based on pyhttpd are included where appropriate, in the
  test/modules/xxx directory matching the modules/xxx module source,
  or test/modules/core for core server changes. On Unix, verify these
  pass locally with e.g. make check-pytest PYTEST_DIRS=test/modules/xxx.

[notroj]

+1