psprintf:

fix a memory leak -- need to block alarms the whole time
the block is being "abused"... easier to do that than it is to massage
p->last each time we have to get a new block.

fix a bug in psprintf_flush, it wouldn't copy properly when moving to
a new block

fix compile errors when compiling with ALLOC_USE_MALLOC


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@81149 13f79535-47bb-0310-9956-ffa450edef68