degesch: fix Lua 5.4 build

Not sure about how well it works yet.

Lua 5.3 is still made preferential by the order of pkgconfig lookup.

CMakeLists.txt

@@ -85,7 +85,7 @@ include_directories (${libffi_INCLUDE_DIRS})
 link_directories (${libffi_LIBRARY_DIRS})
 
 # FIXME: other Lua versions may be acceptable, don't know yet
-pkg_search_module (lua lua53 lua5.3 lua-5.3 lua>=5.3)
+pkg_search_module (lua lua53 lua5.3 lua-5.3 lua54 lua5.4 lua-5.4 lua>=5.3)
 option (WITH_LUA "Enable support for Lua plugins" ${lua_FOUND})
 
 if (WITH_LUA)

degesch.c

@@ -9646,12 +9646,19 @@ lua_task_resume (struct lua_task *self, int index)
 		n = 2;
 	}
 
+#if LUA_VERSION_NUM >= 504
+	int nresults = 0;
+	int res = lua_resume (L, NULL, n, &nresults);
+#else
 	int res = lua_resume (L, NULL, n);
+	int nresults = lua_gettop (L);
+#endif
+
 	struct error *error = NULL;
 	if (res == LUA_YIELD)
 	{
 		// AFAIK we don't get any good error context information from here
-		if (lua_task_schedule (self, lua_gettop (L), &error))
+		if (lua_task_schedule (self, nresults, &error))
 			return;
 	}
 	// For simplicity ignore any results from successful returns