indent(1): Fix memory leaks pointed out by clang-analyzer.

indent(1): Fix memory leaks pointed out by clang-analyzer.

Shift the responsibility of allocating memory for the string duplicate
from the caller (set_option, add_typedefs_from_file) to the callee
(add_typename) as it has more knowledge about when the duplication
actually needs to occur.

Taken from:	Piotr Stefaniak