--data-binary output should be escaped

[salty-horse]

Similar to the -F multipart bugs, the strings after --data-bianry are not escaped.

Given this input:

POST / HTTP/1.1
Host: localhost:8000
User-Agent: curl/7.47.0
Accept: */*
Content-Length: 5
Content-Type: application/x-www-form-urlencoded

$PATH

h2c outputs: curl --http1.1 --user-agent "curl/7.47.0" --data-binary "$PATH" https://localhost:8000/

A POSIX shell will expand $PATH.

[salty-horse]

The same is true for other fields, such as user agent.

[bagder]

Yes, and other headers too.

[salty-horse]

Binary data (specifically non-printable characters) should also be escaped and written as \x##.