Make vm_interrupt and timed_out atomic

On Windows these are already set from another thread and should be
atomic. On Linux it is unclear to me if this should be done based on
the existing code.

However, extensions which use vm interrupts are very likely to do the
same thing that Windows is doing: set a vm_interrupt from another
thread.

This combination suggests to me that this change is overdue.

Author: morrisonlevi

Zend/zend_globals.h

@@ -20,8 +20,8 @@
 #ifndef ZEND_GLOBALS_H
 #define ZEND_GLOBALS_H
 
-
 #include <setjmp.h>
+#include <stdatomic.h>
 
 #include "zend_globals_macros.h"
 
@@ -184,13 +184,17 @@ struct _zend_executor_globals {
 	uint32_t persistent_classes_count;
 
 	HashTable *in_autoload;
+
+	/* sizeof atomic_bool is not guaranteed to be the same as sizeof bool,
+	 * but it's somewhat common. The atomic_bools are left by the other
+	 * bools so that the struct packs nicely for such platforms.
+	 */
+	atomic_bool vm_interrupt;
+	atomic_bool timed_out;
 	bool full_tables_cleanup;
 
 	/* for extended information support */
 	bool no_extensions;
-
-	bool vm_interrupt;
-	bool timed_out;
 	zend_long hard_timeout;
 
 #ifdef ZEND_WIN32