Add checks to maps that are too small.

fixes ticket:2135

git-svn-id: https://warzone2100.svn.sourceforge.net/svnroot/warzone2100/branches/2.3@11585 4a71c877-e1ca-e34f-864e-861f7616d084
(cherry picked from commit 43570ae)

src/map.c

@@ -163,8 +163,13 @@ BOOL mapNew(UDWORD width, UDWORD height)
 
 	if (width*height > MAP_MAXAREA)
 	{
-		debug(LOG_ERROR, "map too large : %u %u", width, height);
+		debug(LOG_ERROR, "Map too large : %u %u", width, height);
+		return false;
+	}
 
+	if (width <=1 || height <=1)
+	{
+		debug(LOG_ERROR, "Map is too small : %u, %u", width, height);
 		return false;
 	}
 
@@ -781,6 +786,12 @@ BOOL mapLoad(char *filename)
 		goto failure;
 	}
 
+	if (width <=1 || height <=1)
+	{
+		debug(LOG_ERROR, "Map is too small : %u, %u", width, height);
+		return false;
+	}
+
 	/* See if this is the first time a map has been loaded */
 	ASSERT(psMapTiles == NULL, "Map has not been cleared before calling mapLoad()!");