Fix isNan on setYaw Lua call (#7380)

* Fix isNan on setYaw Lua call

src/script/lua_api/l_base.cpp

@@ -21,7 +21,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_internal.h"
 #include "cpp_api/s_base.h"
 #include "content/mods.h"
-#include <server.h>
+#include "server.h"
+#include <cmath>
 
 ScriptApiBase *ModApiBase::getScriptApiBase(lua_State *L)
 {
@@ -84,3 +85,8 @@ bool ModApiBase::registerFunction(lua_State *L, const char *name,
 
 	return true;
 }
+
+bool ModApiBase::isNaN(lua_State *L, int idx)
+{
+	return lua_type(L, idx) == LUA_TNUMBER && std::isnan(lua_tonumber(L, idx));
+}