Characters duplicate, newline char gets deleted when handling multi-line string from POST request

[ghost]

When string with empty lines between lines with text is sent as a param of request (e.g. data from webform), the second and every next line with text begins with duplicated characters. Furthermore, the empty lines get deleted.

Example:
we send request through webform with method=post

test test


test test test


test test test test

the program calls onion_request_get_post, which returns

test test
tetest test test
tetest test test test

• Version: 0.8.0
• Code of a simple program that triggers the bug is attached. It's .txt instead of .c as GitHub doesn't allow that.
• Steps to trigger the bug are outlined above and in the program. I'm running Linux on i686 architecture in case it would turn out to be architecture-bound.

code.txt