Work in progress on CORE-3632: make all file descriptors, opened by firebird, close on exec()

git-svn-id: svn://svn.code.sf.net/p/firebird/code/firebird/trunk@60379 65644016-39b1-43b1-bf79-96bc8fe82c15
nightly update

git-svn-id: svn://svn.code.sf.net/p/firebird/code/firebird/trunk@60380 65644016-39b1-43b1-bf79-96bc8fe82c15