* automake.in (&read_am_file): Use $last_where to register the

* automake.in (&read_am_file): Use $last_where to register the
_first_ line of a variable definition as location instead of the
last one.
(&conditional_ambiguous_p): Don't forget to ->string the
Conditionals.
(&rule_define): Likewise.
* tests/location.test: Adjust to exercise this.