[v3] - feat(windows): static embed SAPI build support

[luthermonson]

From the beginning I couldn't really get windows static builds to work in v3 as you can probably tell by my 4 PRs tonight, if for some reason these changes are not welcome because I'm missing something that already works in v3 please let me know.

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Enable building and validating php8embed as a fat static library on Windows (no DLL dependency at runtime). This consists of three Makefile patches and a rewritten compile-time smoke test.

1. CFLAGS_EMBED export defines

   Embed SAPI objects are compiled as DLL consumers by default, so calls into PHP/Zend APIs go through _imp thunks. For a fat static lib they need direct linkage. Inject PHP_EXPORTS, LIBZEND_EXPORTS, SAPI_EXPORTS, TSRM_EXPORTS into CFLAGS_EMBED so php_embed.obj references symbols directly.

2. Strip duplicate TSRM cache definition from php_embed.c

   In DLL builds each SAPI has its own _tsrm_ls_cache via TSRMLS_CACHE_DEFINE(). In our fat static lib all objects share one binary, so php_embed.c's definition collides with zend.c's, producing LNK4006 and a corrupt binary. Remove the duplicate in-source so php_embed.obj uses zend.c's copy.

3. Rewrite embed smoke test

   The PHP_EMBED_START_BLOCK/END_BLOCK macros expand to setjmp/longjmp and a zend_first_try wrapper that doesn't work cleanly when the embed lib's TSRM cache was stripped above. Use the explicit php_embed_init / zend_first_try / php_embed_shutdown form instead.

   Also:

   • Add PHP_EXPORTS/LIBZEND_EXPORTS/SAPI_EXPORTS/TSRM_EXPORTS to the test compile flags (mirroring CFLAGS_EMBED).
   • Add pathcch.lib (PHP 8.x main/streams calls PathCchCanonicalizeEx).
   • Remove /FORCE:MULTIPLE from the link line - no longer needed since the TSRM cache duplicate is fixed at source above.
   • Use str_contains() for output validation instead of exact match, so optional stderr noise from the loaded extensions doesn't break the test.

[luthermonson]

We are going to do this upstream 😨 ill post linked PRs when I get them up and close

[luthermonson]

php/php-src#22166 thanks again for the help @henderkes i think this is right based on the hacks that worked here to get builds working again. let's see if they get through.