From a929ab0c24826e80e01c59fe57b4c6087d59301c Mon Sep 17 00:00:00 2001
From: frosch <frosch@openttd.org>
Date: Wed, 14 Apr 2010 19:56:29 +0000
Subject: [PATCH] (svn r19633) -Fix (r11759): Signed computations with unsigned
 integers.

---
 src/terraform_cmd.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
index b98dc233df..2c45bcc459 100644
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -372,7 +372,7 @@ CommandCost CmdLevelLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 	uint oldh = TileHeight(p1);
 
 	/* compute new height */
-	uint h = oldh + p2;
+	uint h = oldh + (int8)p2;
 
 	/* Check range of destination height */
 	if (h > MAX_TILE_HEIGHT) return_cmd_error((oldh == 0) ? STR_ERROR_ALREADY_AT_SEA_LEVEL : STR_ERROR_TOO_HIGH);