[#58] fix(script): fix function parameters

This commit fixes a crash with higher-order functions. Previously, passing a function as a parameter might cause the callee to copy its value into a local variable which did not have enough space for the function value.

With this fix, one integer of space is allocated for non-const function symbols which should fix that issue.

source/script.cc

@@ -274,6 +274,10 @@ namespace phoenix {
 				sym._m_value = std::shared_ptr<instance> {nullptr};
 				[[fallthrough]];
 			case datatype::function:
+				if (!sym.is_const()) {
+					sym._m_value = std::unique_ptr<std::int32_t[]>(new int32_t[1]);
+				}
+				[[fallthrough]];
 			case datatype::prototype:
 				sym._m_address = in.get_int();
 				break;