Subject: building with -Werror=format-security fails

Also, some invocations of croak() are missing the arguments placeholders.

Bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=661381

--- a/BerkeleyDB.xs
+++ b/BerkeleyDB.xs
@@ -949,7 +949,7 @@ softCrash(const char *pat, ...)
 
     vsprintf(buffer2, buffer1, args) ;
 
-    croak(buffer2);
+    croak("%s", buffer2);
 
     /* NOTREACHED */
     va_end(args);
@@ -2747,7 +2747,7 @@ _db_appinit(self, ref, errfile=NULL)
 	    if (SvOK(errfile)) {
 	        FILE * ef = GetFILEptr(errfile);
 	    	if (! ef)
-		    croak("Cannot open file ErrFile", Strerror(errno));
+		    croak("Cannot open file ErrFile: %s", Strerror(errno));
 		RETVAL->ErrHandle = newSVsv(errfile) ;
 	    	env->set_errfile(env, ef) ;
 
@@ -2759,7 +2759,7 @@ _db_appinit(self, ref, errfile=NULL)
 	        if (SvOK(msgfile)) {
 	            FILE * ef = GetFILEptr(msgfile);
 	    	    if (! ef)
-		        croak("Cannot open file MsgFile", Strerror(errno));
+		        croak("Cannot open file MsgFile: %s", Strerror(errno));
 		    RETVAL->MsgHandle = newSVsv(msgfile) ;
 	    	    env->set_msgfile(env, ef) ;
 	        }
