fix: update TSRMLS cache in APCu serializer callbacks on ZTS

The APCu (un)serializer callbacks are invoked from APCu's translation
unit, where brotli's per-module _tsrm_ls_cache is not refreshed for the
current thread. On ZTS shared builds this left the cache stale, so
PHP_VAR_SERIALIZE_INIT dereferenced a bad pointer when accessing basic
globals via BG(), crashing with SIGSEGV. NTS passed because it has no
TSRMLS cache and BG() resolves directly.

Refresh the cache with ZEND_TSRMLS_CACHE_UPDATE() at the entry of both
callbacks, mirroring php_brotli_output_encoding().

Author: kjdev

brotli.c

@@ -1843,6 +1843,9 @@ static ZEND_FUNCTION(brotli_uncompress_add)
 #if defined(HAVE_APCU_SUPPORT)
 static int APC_SERIALIZER_NAME(brotli)(APC_SERIALIZER_ARGS)
 {
+#if defined(COMPILE_DL_BROTLI) && defined(ZTS)
+    ZEND_TSRMLS_CACHE_UPDATE();
+#endif
     int result;
     int lgwin = BROTLI_DEFAULT_WINDOW;
     long level = BROTLI_G(apcu_compression_level);
@@ -1883,6 +1886,9 @@ static int APC_SERIALIZER_NAME(brotli)(APC_SERIALIZER_ARGS)
 
 static int APC_UNSERIALIZER_NAME(brotli)(APC_UNSERIALIZER_ARGS)
 {
+#if defined(COMPILE_DL_BROTLI) && defined(ZTS)
+    ZEND_TSRMLS_CACHE_UPDATE();
+#endif
     const uint8_t *next_in = (const uint8_t*) buf;
     const unsigned char* tmp;
     int result;