diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2d2635f05..9bd567d24 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -48,7 +48,9 @@ endif()
 find_package(EXPAT REQUIRED)
 find_package (ToLua REQUIRED)
 if (TOLUA_FOUND)
-if (${TOLUA_VERSION_STRING} VERSION_EQUAL "5.2")
+if (${TOLUA_VERSION_STRING} VERSION_EQUAL "5.3")
+find_package (Lua 5.3 REQUIRED)
+elseif (${TOLUA_VERSION_STRING} VERSION_EQUAL "5.2")
 find_package (Lua 5.2 REQUIRED)
 else ()
 find_package (Lua51 REQUIRED)
diff --git a/s/cmake-init b/s/cmake-init
index 22d98b42e..a8228c379 100755
--- a/s/cmake-init
+++ b/s/cmake-init
@@ -79,13 +79,16 @@ git submodule update --init
 LUA_VERSION="5.2"
 LUA_INCLUDE=/usr/include
 LUA_DIR=/usr
-if [ -d /usr/include/lua5.1 ]; then
-   LUA_VERSION="5.1"
-   LUA_INCLUDE=/usr/include/lua5.1
+if [ -d /usr/local/include/lua5.3 ]; then
+   LUA_VERSION="5.3"
+   LUA_INCLUDE=/usr/local/include/lua5.3
 elif [ -d /usr/include/lua5.2 ]; then
    export LUA_DIR=/usr
    LUA_VERSION="5.2"
    LUA_INCLUDE=/usr/include/lua5.2
+elif [ -d /usr/include/lua5.1 ]; then
+   LUA_VERSION="5.1"
+   LUA_INCLUDE=/usr/include/lua5.1
 elif [ -d /usr/local/include/lua5.1 ]; then
    export LUA_DIR=/usr/local
    LUA_VERSION="5.1"
diff --git a/src/laws.c b/src/laws.c
index fc1c8dc88..01aa4be8d 100644
--- a/src/laws.c
+++ b/src/laws.c
@@ -684,7 +684,7 @@ growing_trees(region * r, const season_t current_season, const season_t last_wee
             a->data.sa[0] = (short)cap_int(rtrees(r, 0), 0, SHRT_MAX);
             a->data.sa[1] = (short)cap_int(rtrees(r, 1), 0, SHRT_MAX);
         }
-        else if (a->data.sa[0] < 0 || a->data.sa[1] << 0) {
+        else if (a->data.sa[0] < 0 || a->data.sa[1] < 0) {
             a->data.sa[0] = (short)cap_int(a->data.sa[0], 0, SHRT_MAX);
             a->data.sa[1] = (short)cap_int(a->data.sa[1], 0, SHRT_MAX);
         }