#include <cstring> in guetzli.cc

[shrx]

Fixes #12

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[robryk]

LGTM

Will merge as soon as clabot is happy. Thanks for bearing with the bureaucracy.

[shrx]

Hello, I do not wish to submit all the personal data required to sign your CLA.

[robryk]

I am terribly sorry, but signing a CLA is a hard requirement for legal reasons. Likewise the requirement that you provide an address and a contact phone when doing so.

I shan't merge a patch for which that is not satisfied. Sorry again.