Simplify console output helpers

[andypost]

Simplify console output helpers

Follow-up to #629, per @madmajestro's review suggestion there.

Replaces the APC_PRINT_FUNCTION generator in apc.c — which produced four
exported apc_error / apc_warning / apc_notice / apc_debug functions —
with thin variadic macros in apc.h that forward straight to
php_error_docref():

#define apc_error(...)   php_error_docref(NULL, E_ERROR,   __VA_ARGS__)
#define apc_warning(...) php_error_docref(NULL, E_WARNING, __VA_ARGS__)
#define apc_notice(...)  php_error_docref(NULL, E_NOTICE,  __VA_ARGS__)

Net −16 lines, and it supersedes #629: the old generator body called
php_verror(), whose signature changed in php/php-src@0a12b3e8268 (params arg
removed) and broke the build against PHP 8.6-dev. Forwarding to
php_error_docref() sidesteps php_verror() entirely and builds on all
supported versions. If this lands, #629 can be closed.

Trade-off: ABI

Pro — simpler (no apc.c code, no va_list/vspprintf/efree
plumbing), one fewer indirection, and format-string checking is preserved via
php_error_docref's own printf attribute. apc_debug also stops evaluating
its arguments when APC_DEBUG is off (do {} while (0)), which is the usual,
slightly-better behaviour.

Con — the four functions were declared PHP_APCU_API, i.e. exported
symbols; turning them into macros removes them from the ABI. They're internal
console helpers (no in-tree or bc/ caller takes their address or uses them
outside a direct call), so the practical risk is nil — but it is technically a
public-symbol removal, hence a separate PR for you to decide rather than folded
into the #629 build-fix.

Verification

• All translation units that use these macros compile clean against php-src
  master (new 4-arg php_verror present in main/php.h).
• Counter-check: pristine master apcu fails the same compile on the
  php_verror argument mismatch — the exact break Fix build against PHP 8.6 (php_verror params argument removed) #629 addresses — confirming
  the fix is real and not a no-op.
• APC_DEBUG=1 build compiles; no -Wunused fallout from the disabled
  apc_debug.

[andypost]

Supersedes #629 (the minimal php_verror build-fix). This PR fixes the same PHP 8.6-dev build break and additionally applies @madmajestro's cleanup suggestion from that review. If this is preferred, #629 can be closed; if the ABI removal is unwanted, #629 remains the minimal fix.

[andypost]

Pushed a small refinement: with APC_DEBUG off, apc_debug is now

do { if (0) php_error_docref(NULL, E_NOTICE, __VA_ARGS__); } while (0)

instead of a bare do {} while (0). The if (0) keeps compile-time -Wformat checking of debug call sites in normal (non-debug) builds at zero runtime cost — verified that a deliberately mismatched format in an apc_debug() call now warns even without --enable-apcu-debug. Previously a bad debug format would only surface in debug builds, which CI doesn't exercise.

[madmajestro]

LGTM! Thank you!

I think this ABI break is more of a theoretical issue. No other PHP extension should rely on APCu logging functions that were quite obviously intended for internal use. Especially since that functionality is also available via php_error_docref() in the PHP core. Not even the apcu-bc extension depends on these functions.

[andypost]

Thank you, awaiting beta stability of 8.6 now