Mgv6: Add fallback node for gravel

Gravel now falls back to stone.
Gravel is not a particularly fundamental node, allowing it to fall back
to stone frees up subgames from having to include a gravel node.
Non-blob-ore gravel is only present in mgv6 as extremely rare 'gravel
biomes'.

diff --git a/src/mapgen_v6.cpp b/src/mapgen_v6.cpp
index d4e3fa8d765871420601c2b214d8045256de67f9..807bbe7517f675f1dc8fb095921f0a37b6421f66 100644 (file)
--- a/src/mapgen_v6.cpp
+++ b/src/mapgen_v6.cpp
@@ -99,6 +99,8 @@ MapgenV6::MapgenV6(int mapgenid, MapgenV6Params *params, EmergeManager *emerge)
        c_snowblock       = ndef->getId("mapgen_snowblock");
        c_ice             = ndef->getId("mapgen_ice");
 
+       if (c_gravel == CONTENT_IGNORE)
+               c_gravel = c_stone;
        if (c_desert_stone == CONTENT_IGNORE)
                c_desert_stone = c_stone;
        if (c_desert_sand == CONTENT_IGNORE)