Add --enable-embed=static support on Windows

PHP's Unix build already documents and accepts --enable-embed=static
(see sapi/embed/config.m4) for building php<N>embed as a static library
with no DLL at runtime. The Windows config.w32 ignored the static
value, leaving php_embed.c compiled as a DLL consumer regardless.

When --enable-embed=static is passed on Windows:

* Inject /D PHP_EXPORTS /D LIBZEND_EXPORTS /D SAPI_EXPORTS
  /D TSRM_EXPORTS into CFLAGS_EMBED so php_embed.c references PHP/
  Zend/SAPI/TSRM symbols directly instead of through __declspec(
  dllimport) thunks (which would produce LNK2019 with no DLL).

* Skip php_embed.c's ZEND_TSRMLS_CACHE_DEFINE() (gated on the new
  PHP_EMBED_STATIC define). In static mode zend.c is in the same
  link unit and already defines _tsrm_ls_cache; the duplicate from
  php_embed.c produced LNK4006 / corrupt binary.

This patches only the source-side adjustments; producing a fat
static lib (linking PHP_GLOBAL_OBJS + STATIC_EXT_OBJS into
php<N>embed.lib) is a downstream Makefile concern.

Author: luthermonson

NEWS

@@ -2,6 +2,13 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 8.5.8
 
+- Embed:
+  . Added --enable-embed=static support on Windows: when selected, php_embed.c
+    is compiled with PHP/Zend/SAPI/TSRM export defines so it references core
+    symbols directly instead of through dllimport thunks, and its duplicate
+    TSRMLS cache definition is skipped (zend.c provides it in the same
+    link unit). (Luther Monson)
+
 - GD:
   . Fixed bug GH-22121 (Double free in gdImageSetStyle() after
     overflow-triggered early return). (iliaal)

sapi/embed/config.w32

@@ -6,5 +6,15 @@ var PHP_EMBED_PGO = false;
 
 if (PHP_EMBED != "no") {
 	SAPI('embed', 'php_embed.c', 'php' + PHP_VERSION + 'embed.lib', '/DZEND_ENABLE_STATIC_TSRMLS_CACHE=1');
+	if (PHP_EMBED == "static") {
+		// Static embed mode: php<N>embed.lib is intended to contain PHP
+		// core, extensions and the embed SAPI in a single static library
+		// (no php<N>.dll at runtime). php_embed.c must reach PHP/Zend/
+		// SAPI/TSRM symbols directly rather than through dllimport thunks.
+		ADD_FLAG('CFLAGS_EMBED',
+			'/D PHP_EMBED_STATIC' +
+			' /D PHP_EXPORTS /D LIBZEND_EXPORTS' +
+			' /D SAPI_EXPORTS /D TSRM_EXPORTS');
+	}
 	PHP_INSTALL_HEADERS("sapi/embed", "php_embed.h");
 }

sapi/embed/php_embed.c

@@ -30,7 +30,7 @@ static const char HARDCODED_INI[] =
 	"max_execution_time=0\n"
 	"max_input_time=-1\n\0";
 
-#if defined(PHP_WIN32) && defined(ZTS)
+#if defined(PHP_WIN32) && defined(ZTS) && !defined(PHP_EMBED_STATIC)
 ZEND_TSRMLS_CACHE_DEFINE()
 #endif