* data/location.cc: New, extract from...

* data/location.cc: New, extract from...
* data/lalr1.cc: here.
(location.hh): Include it after the user prologue, in case the
filename type is defined by the user.
Forward declation location and position before the pre-prologue.
(yyresult_): Rename as...
(yyresult): this, it's a local variable, not an attribute.
* data/Makefile.am (dist_pkgdata_DATA): Adjust.