diff --git a/src/sys/driver.h b/src/sys/driver.h
index 35f5cd9b..b884064b 100644
--- a/src/sys/driver.h
+++ b/src/sys/driver.h
@@ -65,6 +65,7 @@ extern __declspec(selectany) int fsp_bp_ioprep = 1; /* I/O prepare breakpoint sw
 extern __declspec(selectany) int fsp_bp_iocmpl = 1; /* I/O complete breakpoint switch */
 extern __declspec(selectany) int fsp_bp_iocall = 1; /* I/O callback breakpoint switch */
 extern __declspec(selectany) int fsp_bp_iorecu = 1; /* I/O recursive breakpoint switch */
+extern __declspec(selectany) int fsp_bp_crit = 1;   /* critical error breakpoint */
 #define DEBUGBREAK()                    \
     do                                  \
     {                                   \