Linux platforms have various differences that make it difficult to enable

the HAVE_SHMGET and disable the USE_FCNTL_SERIALIZED_ACCEPT reliably.  So
instead we'll let the user shoot themselves.

Reviewed by:	Jim, Ralf, Chuck


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@77901 13f79535-47bb-0310-9956-ffa450edef68