simplify allocation and fix memory leak

[kloetzl]

• sizeof(char) is defined as 1
• use malloc, as we don't use zero-initialisation
• don't cast return value 1
• as we know the length of the string, use memcpy
• also fixes memory leak

using strdup might make things even simples

[andrewjpage]

Thanks for the fixes.

[kloetzl]

You are welcome!