Revert "Export opcache shared globals (php#15543)"

This reverts commit b9b317a.  We
don't need it and the use of ZEND_EXT_API would require us to include
ZendAccelerator.h.

Author: MaxKellermann

ext/opcache/zend_shared_alloc.c

@@ -53,7 +53,7 @@
 static const zend_shared_memory_handlers *g_shared_alloc_handler = NULL;
 static const char *g_shared_model;
 /* pointer to globals allocated in SHM and shared across processes */
-ZEND_EXT_API zend_smm_shared_globals *smm_shared_globals;
+zend_smm_shared_globals *smm_shared_globals;
 
 #ifndef ZEND_WIN32
 #ifdef ZTS

ext/opcache/zend_shared_alloc.h

@@ -119,7 +119,7 @@ typedef struct _zend_smm_shared_globals {
 	size_t                     reserved_size;
 } zend_smm_shared_globals;
 
-ZEND_EXT_API extern zend_smm_shared_globals *smm_shared_globals;
+extern zend_smm_shared_globals *smm_shared_globals;
 
 #define ZSMMG(element)		(smm_shared_globals->element)