Get it to build on FreeBSD by dropping <stropt.h>. (It still

builds on Linux.)

Pass an initialized thread attribute instead of an accidental
autodata value to apr_create_signal_thread().  This should
avoid a segfault.  It seemed to behave a little better for me
at this point.

Get rid of some warnings.

gcc on FreeBSD still warns about a few variables that might be
clobbered by longjmp() in worker_thread().


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@88283 13f79535-47bb-0310-9956-ffa450edef68