Fix allocs in function_cache and value_to_c_string

c/ton/main.c

		int max_suffix_len = 20;
		int prefix_len = strlen(cache_prefix);
		char *path = malloc((prefix_len + max_suffix_len) * sizeof(char));
		memset(path, 0, prefix_len + max_suffix_len);
		suffix = ".js";
		strncpy(path, cache_prefix, prefix_len);
		path[prefix_len] = '\0';
		strncat(path, suffix, strlen(suffix));
		strcpy(path, cache_prefix);
		strcat(path, suffix);
		write_contents(path, source);
		suffix = ".cache.json";
		strncpy(path, cache_prefix, prefix_len);
		path[prefix_len] = '\0';
		strncat(path, suffix, strlen(suffix));
		strcpy(path, cache_prefix);
		strcat(path, suffix);
		write_contents(path, cache);
		suffix = ".js.map.json";
		strncpy(path, cache_prefix, prefix_len);
		path[prefix_len] = '\0';
		strncat(path, suffix, strlen(suffix));
		strcpy(path, cache_prefix);
		strcat(path, suffix);
		write_contents(path, sourcemap);
		free(cache_prefix);
	}
	JSStringRef str_ref = JSValueToStringCopy(ctx, val, NULL);
	size_t len = JSStringGetLength(str_ref);
	size_t len = JSStringGetLength(str_ref) + 1;
	char *str = malloc(len * sizeof(char));
	memset(str, 0, len);
	JSStringGetUTF8CString(str_ref, str, len);
	JSStringRelease(str_ref);