rcutil: split osrcpath to return default.d paths (API)
After this change, there are 3 rcpath functions:
- defaultrcpath
- systemrcpath
- userrcpath
This will allow us to insert another config layer in the middle.
$ hg init
$ touch a
$ unset HGUSER
$ echo "[ui]" >> .hg/hgrc
$ echo "username= foo" >> .hg/hgrc
$ echo " bar1" >> .hg/hgrc
$ hg ci -Am m
adding a
abort: username 'foo\nbar1' contains a newline
[255]
$ rm .hg/hgrc
$ HGUSER=`(echo foo; echo bar2)` hg ci -Am m
abort: username 'foo\nbar2' contains a newline
[255]
$ hg ci -Am m -u "`(echo foo; echo bar3)`"
transaction abort!
rollback completed
abort: username 'foo\nbar3' contains a newline!
[255]