Do not close automatically on write error. The internal ssl_write_callback() would call shutdown() on write error, which would cause the object to enter one of the closed states, without the user actually having closed the file. This in turn caused errors like "Not open" from functions like read() and set_nonblocking().
The module's configure script now respects ABI suffixes when searching
for the sybase library dir.
o Thread.Queue Attempt to work around glibc bugs. Glibc 2.24 and earlier have a broken implementation of condition variables (cf https://sourceware.org/bugzilla/show_bug.cgi?id=13165). Attempt to work around the issue by having the signalling thread release the associated mutex before signalling.