Add a warning for an address expression that is usually the result of a typo

and almost never used in this form.


git-svn-id: svn://svn.cc65.org/cc65/trunk@2158 b7a2c559-68d2-44c3-8de9-860c34a00d81

src/ca65/error.h

@@ -55,6 +55,7 @@ enum Warnings {
     WARN_SYM_NOT_REFERENCED,
     WARN_IMPORT_NOT_REFERENCED,
     WARN_CANNOT_TRACK_STATUS,
+    WARN_SUSPICIOUS_ADDREXPR,
     WARN_USER,
     WARN_COUNT	     	    	      	/* Warning count */
 };