hdf5

[svn-r4987] Purpose:
	Bug Fix
Description:
	When doing an install of dynamic executables on some platforms, the
	"mktemp" command may fail which causes the contents of "tmpdir" to go
	away. If it's a failure, we still need the previous value of tmpdir.
Solution:
	I replicated some code so that tmpdir's old value before the mktemp
	call is regen'ed if the mktemp call failed.
Platforms tested:
	HP-UX SysV