* ltmain.in, ltconfig.in: reverted most of the quoting changes

* ltmain.in, ltconfig.in: reverted most of the quoting changes
from 1999-03-25; Gary's delay_variable_subst patch from 1999-02-19
obviates it.  Keep only quoting of $PATH, for uniformity with
other systems that already did it
* TODO: comments on hardcoding paths into libraries; problem
with shell meta-characters in filenames