reword the error msg so people realize that they broke it, they buy it
diff --git a/shell/ash.c b/shell/ash.c
index 31beb86..a8428b9 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -10765,7 +10765,7 @@
 #if ENABLE_ASH_MATH_SUPPORT
 			PARSEARITH();
 #else
-			raise_error_syntax("We unsupport $((arith))");
+			raise_error_syntax("you disabled math support for $((arith)) syntax");
 #endif
 		} else {
 			pungetc();