Fix build

ext/standard/exec.h

@@ -21,6 +21,10 @@
 #ifndef EXEC_H
 #define EXEC_H
 
+#define ESCAPE_CMD_PAIR  0 
+#define ESCAPE_CMD_END   1 
+#define ESCAPE_CMD_ALL   2
+
 PHP_FUNCTION(system);
 PHP_FUNCTION(exec);
 PHP_FUNCTION(escapeshellcmd);