1. Support cygwin by '--cygwin64=on'
2. Detect cygwin automatically.
3. Disalbe sanitizer, srt and srtp with openssl.
4. Disable multiple threads, use single threads.
5. Support utest for cygwin64.
6. Query features for windows by API.
7. Disable stat APIs for cygwin.
8. Use ST select event driver.
Co-authored-by: wenjie.zhao <740936897@qq.com>
1. Replase ln by cp for windows.
2. Refine OS and CPU arch detecting.
3. Support configure from any directory by `SRS_WORKDIR`.
4. Support output to any directory by `SRS_OUTPUT`.
5. Disable sanitizer for gperf.
6. Use parallels build for make.
7. Refine bash variable check.