Add BlGetBooleanParameter declaration

xtldr/includes/xtldr.h

@@ -128,6 +128,11 @@ XTCDECL
 EFI_STATUS
 BlFreeMemoryPool(IN PVOID Memory);
 
+XTCDECL
+BOOLEAN
+BlGetBooleanParameter(IN CONST PWCHAR Parameters,
+                      IN CONST PWCHAR Needle);
+
 XTCDECL
 BOOLEAN
 BlGetConfigBooleanValue(IN CONST PWCHAR ConfigName);