Disable builds for MacOS in Travis CI.
Disable builds for MacOS in Travis CI.

Apparently Travis CI is charging for MacOS X builds, even if you are already paying for a concurrency based plan. This seems to be breaking our builds. See: https://docs.travis-ci.com/user/billing-overview/#travis-ci-plan-types

hillu/yara,pombredanne/yara,wxsBSD/yara,hillu/yara,VirusTotal/yara,pombredanne/yara,pombredanne/yara,wxsBSD/yara,VirusTotal/yara,VirusTotal/yara,VirusTotal/yara,VirusTotal/yara,hillu/yara,hillu/yara,pombredanne/yara,wxsBSD/yara,wxsBSD/yara,pombredanne/yara,wxsBSD/yara,hillu/yara